GB/T 2886-1992 Technical requirements for intercommunication between type 2 document fax machines in the telephone network
Some standard content:
UDC621.395：621.397.12
National Standard of the People's Republic of China
GB/T 2886—92
Technical requirements for group 2document facsimile apparatus used in public telephone networkPublished on 1992-12-19
State Administration of Technical Supervision
Implementation on 1993-08-01
National Standard of the People's Republic of China
Technical requirements for group 2document facsimile apparatus used in public telephone network network
GB/T2886-92
Replaces GB2886-82
This standard equivalently adopts the provisions applicable to the second type of document fax machines in CCITT Recommendation T.3 "Standardization of document fax machines" and Recommendation T.30 "Transmission procedures for document fax machines on the public telephone network". 1 Subject content and scope of application
This standard specifies the technical requirements for the scanning direction, original size, scanning parameters, scanning line frequency, phase, message transmission, modulation and demodulation, transmitter output level, receiver input level, transmission procedures, etc. of the second type of document fax machines. This standard is the interoperability technical conditions for the second type of document fax machines used on the telephone automatic switching network and dedicated circuits (frequency band of 300~3400Hz), and is the basis for the design and operation of the second type of document fax machines. 2 Reference standards
GB3382 Technical conditions for intercommunication of voice-based fax machines in the telephone network 3 Technical conditions for intercommunication of document fax machines of type II in the telephone network 3.1 Scanning direction
The movement of the scanning point of the transmitter and the receiver on the original or recording surface is from left to right, and the scanning lines are adjacent from top to bottom, that is, the scanning point starts from the upper left corner of the scanning field and ends at its lower right corner. Note: In order to avoid loss of information, the user should make the scanning direction from the wide blank edge to the narrow blank edge when inserting the file. 3.2 Original size
ISOA4 size (nominal 210mm×297mm) is adopted. 3.3 Scanning parameters
3.3.1 Cooperation factor (FOC) is 829±8.3 (the corresponding cooperation index is 264±2.64). 3.3.2 Total length of scanning line (TLL) is 215mm. 3.3.3 The minimum effective scanning line length (ULL) is 205mm, and the end of the effective scanning line length is located 0~1mm within the nominal position of the right edge of the ISOA4 size document.
3.3.4 The scanning density is 3.85 lines/mm.
3.4 Scanning line frequency
3.4.1 The scanning line frequency is 360 lines/min.
3.4.2 During the transmission process, the scanning line frequency deviation is maintained within ±5×10- of the nominal value. 3.5 Phase alignment
Before the message information is transmitted, the transmitter sends a signal as shown in Figure 1, starts to send a carrier, and indicates that the loss time (the C interval in Figure 1 approved by the State Administration of Technical Supervision on December 19, 1992 and implemented on August 1, 1993) ends. The adjustment accuracy from the end of the transmitter loss time to the start of the carrier should be ±0.5% of the full length of the scan line. The phase reference point of the receiver is aligned with the start point of the transmitter carrier, and its adjustment accuracy is ±1% of the full length of the scan line. This reference point should be 209mm before the end of the effective length of the scan line (see Figure 2).
Note: When transmitting multiple pages, the phase needs to be re-aligned between each page.
Figure 1 Structure of line regulation signal and phase signal LCS-1100±50Hz, the transmission of this signal is optional A-send the carrier with 0° phase for 94%~96% of the total length of the scan line; B-send the carrier with 180° phase for the same length as A; C-no signal for the remaining 4%~6% of the total length of the scan line (the level is at least 26dB lower than the interval between A and B) ULLA2JEmM
3.6 Message transmission
ILE 25mm
Figure 2 Receiver phase reference point
3.6.1 During the transmission of message information, the transmitter shall send the full amplitude carrier for at least 4% of the total length of the transmission scan line during the loss time, and the phase of the carrier shall be converted by 180° at the end of this signal. After the loss time, the information transmitted to the receiver is the information contained in the effective length of the scan line. 3.6.2 The receiver can make an amplitude reference independent of the message signal based on the signal described in 3.6.1, and indicate that the message is still being transmitted. 3.7 Paper page positioning
The fax machine should ensure that the paper page is positioned within the nominal value ±1.5mm in the horizontal direction, and the positioning in the vertical direction should ensure that the scanning and recording starts within 4mm below the upper edge of the message. 3.8 Modulation and demodulation
3.8.1 The residual sideband amplitude modulation-phase modulation method is adopted. The carrier frequency is 2100 ±10Hz, the white signal is represented by the full amplitude carrier, and the black signal is represented by no carrier or a carrier at least 26dB lower than the white signal amplitude. After each black-to-white transition, the carrier phase of the white signal should be converted by 180
3.8.2 Fax transmission can contain limited halftones and be represented by a carrier amplitude lower than that sent during the loss time. 3.8.3 The transmitter shall be equipped with a residual sideband filter that is symmetrical with respect to the 2100Hz carrier frequency. The characteristic curve of the filter shall comply with the provisions of Figure 3. The relative transmission coefficient at the carrier frequency is 0.5, and its allowable deviation is ±0.05. In the frequency range of 12003000Hz, the frequency characteristic shall be obviously oddly symmetrical with respect to the carrier frequency. 3.8.4 The receiver can still work normally when the carrier frequency deviates from the nominal value by no more than ±16Hz. 3.8.5 A fixed compromise equalizer, automatic equalizer or adaptive equalizer may be set in the receiver. in
3.9 Transmitter output level
Figure 3 Frequency response of residual sideband filter
Frequency, kHz
The white signal level is adjustable from -15 to 0dBm, but the operator cannot adjust it at will. The black signal level is at least 26dB lower than the white signal level.
3.10 Receiver input level
When the input white signal level varies within the range of 0 to -40dBm, the receiver should be able to operate normally without the operator having to adjust the receiving sensitivity.
3.11 Transmission procedures and transmission control signals
The transmission procedures should comply with the relevant provisions of GB3382. The transmission control signals should comply with the provisions of Chapter 4 of GB3382. 3
A1 Horizontal loss
GB/T2886—92
Appendix A
Ensuring reproducible area for type 2 machines that comply with this standard (supplement))
Figure A1 Ensuring reproducible area for type 2 machines using ISOA4 size paper sheets Figure A2 Horizontal loss for type 2 machines that comply with this standard a-phase loss of the transmitter (±0.5%); 6-phase loss of the receiver (±1.0%); c-skew loss (at the bottom of the paper sheet) (±10-5) d-loss caused by magnification when using different TLL values. This value is only applicable to ULL and the right and bottom margins, because the phase process aligns the ULL of the transmitter and receiver to the same position at the beginning, and the loss caused by incorrect paper insertion is allowed to deviate by ±1.5mm. ——Loss caused by the allowable deviation of ULL relative to A4 size 4
Loss time
Horizontal loss
Transmitter
Receiver
TLL:215~222mm
ULL:205~210mm
Vertical loss
GB/T2886-92
±5×10-6
Offset value
Left margin, mm
Right margin, mm
Paper jam loss
Enlargement+FOC
Other countries
GB/T2886-92
According to the reading
g——Paper jam loss caused by the paper feeding mechanism (at the top of the document: 4.00mm); h - loss caused by incorrect paper insertion, - loss caused by deviation of magnification and cooperation factor (loss of 59 lines)
Top, mm
Bottom, mm
B1 Subject content and scope of application
GB/T2886-92
Appendix B
Technical conditions for intercommunication of selected document fax type II machines in telephone network
(Supplement)
This appendix is the technical conditions for intercommunication of selected document fax type II machines in telephone manual switching network and dedicated circuits (frequency band is 300～3400Hz).
B2 Reference standards
The standards used in conjunction are GB148 "Format size of paper for printing, writing and drawing". B3 Technical conditions for the intercommunication of the selected document fax type II machines in the telephone network B3.1 Original size
Adopt the B4 (186mm×263mm) size of GB148. B3.2 Scanning direction
The movement of the scanning point of the transmitter and the receiver on the original or recording surface is from left to right, and the scanning lines are adjacent from top to bottom, that is, the scanning point starts from the upper left corner of the scanning field and ends at its lower right corner. B3.3 Scanning parameters
B3.3.1 The cooperation factor is 829±8.3 (the corresponding cooperation index is 264±2.64). B3.3.2 The total length of the scanning line is 191.2mm (allowed to be extended to 195mm). B3.3.3 The scanning density is 4.33 lines/mm
B3.3.4 The scanning line frequency is 360 lines/min.
During the transmission process, the frequency deviation of the scanning line should be kept within ±10X10-6. B3.4 Effective transmission area
The effective transmission area is not less than 165mm×250mm. B3.5 Phase
Phase before the message is transmitted. The duration of the transmitter sending the phase signal is 6~7s. The signal structure is shown in Figure B1. The carrier start point is located at the trailing edge of the C signal, and the receiver phases at the trailing edge of the C signal. The distance between the trailing edge of the C signal and the center of the empty segment is 2%~3% of the total length of the scanning line. The receiver phase deviation does not exceed ±2% of the total length of the scanning line. For the signal ~75 and when 1% - Scan or:
Figure B1 Phase signal structure
A-send a carrier with a 0° phase during 94% to 96% of the total length of the scan line; B-send a carrier with a 180° phase for the same time length as A; C-no signal during the remaining 6% to 4% of the total length of the scan line (the level is at least 26dB lower than the intervals A and B)7
B3.6 Reference signal
GB/T2886-92
During the message transmission, the transmitter should send a full-amplitude carrier at the position equivalent to the above C signal. At the end of this signal, the carrier phase should be converted by 180°. The receiver can use this signal as a reference for amplitude and phase, and indicate that the message is still being transmitted. B3.7 Modulation and demodulation
B3.7.1 Use residual sideband amplitude modulation-phase modulation. The carrier frequency is 2250±2Hz. The white signal is represented by a full-amplitude carrier, and the black signal is represented by no carrier or a carrier with an amplitude at least 26dB lower than the white signal. The phase of the black signal changes by 180° each time. If a halftone image with a limited number of levels is transmitted, different colors are distinguished by different carrier amplitudes. B3.7.2 The residual sideband filter is placed in the transmitter. The relative transmission coefficient of the filter at the carrier frequency should be 0.5, with a deviation of ±0.05. The frequency characteristic should be odd-symmetrical to the carrier frequency within the frequency range of 1500 to 3000Hz, and the odd-symmetrical deviation should be within ±10%. The group delay distortion within the frequency range of 500 to 3000Hz is not greater than 500μs. B3.7.3 The receiver can still work normally when the carrier frequency deviates from the nominal value by ±16Hz. B3.7.4 The receiver can be set with an amplitude equalizer as needed. B3.8 Transmitter output level
The white signal level adjustment range of the transmitter output to the line is -15 to 0dBm. The black signal level should be at least 26dB lower than the white signal level.
B3.9 Receiver input level
Receiver input level (white signal) should be able to work normally within the range of 0～
B3.10 Coordination between fax machine and telephone circuit
-40dBm, and its sensitivity does not need to be adjusted manually. B3.10.1 Fax machines used in telephone exchange networks should have network controllers that can be used alternately with telephones. Fax machines used on dedicated circuits should have the performance of 2-wire or 4-wire access. B3.10.2 The output impedance of the transmitter and the input impedance of the receiver are 600±100Q (balanced) in the frequency band of 500～3000Hz.
B3.10.3 The receiver should be able to work normally when the signal-to-noise ratio is not less than 13dB. Note: The signal-to-noise ratio refers to the ratio of the white signal power to the non-weighted value of the white noise power in the 300～3400Hz band. B3.11 Control
The receiver sends a "waiting" signal, indicating that the receiver is in the receiving state, and its duration is 3 to 6 seconds. Sending a "phase confirmation" signal indicates that the receiver has completed the phase, and there should be an indication on the transmitter. Either the transmitter or the receiver sends a "stop" signal, and there should be an indication on the other party's fax machine to indicate that the fax transmission needs to be interrupted and a telephone connection needs to be established.
The above control signals are all 600±10Hz continuous sinusoidal signals, and their levels are the same as the fax signal levels. Manually operated fax machines must comply with the operating procedures in the following table. Automatically operated fax machines should be able to communicate with manually operated fax machines. Manual operation procedure
Status and function
0. Before establishing the circuit
1. Establishing the circuit
2. Notifying the message
Calling station
The line is connected to the telephone
The operator prepares to send the message, picks up the phone, dials and listens to the ringback tone
Hears the "waiting to receive" signal on the telephone
Signal direction
Called station
The line is connected to the telephone
Hear the ringing tone
Transfer the line to the fax machine, start the receiver, and send out the "waiting to receive" signal at the same time
Status and function
3. Fax transmission
4. During fax transmission, the host
calls the station
5. During fax transmission, the receiver
calls the station
6. Telephone contact (receiving state 1)
7. Fax transmission
8. Call the called station
9. Receive confirmation and end transmission
10. Disconnect
GB/T2886—92
Calling station
Receive the "waiting to receive" signal, transfer the line to the fax machine, start the transmitter, send out the phase signal, and then automatically import the transmission message after 6~7s. Receive the "phase confirmation" signal
Send the "stop" signal and transfer the line to the telephone
Receive the "stop" signal Signal, transfer the line to the telephone
Telephone contact or after listening to the "waiting to receive" signal, if you still need to contact, send the "stop" signal
Conversation completed, repeat state 2 and 3
Transmission completed, stop, send the "stop" signal, and transfer the line to the telephone
Notify that the message has been sent
Conversation ended, hang up
Note: 1) The receiving end sends a ringing tone to the receiving station and a ringback tone to the calling station. Signal direction
2) For equipment that can transmit multiple pages continuously, the adjacent pages can be re-aligned when necessary. Additional remarks:
This standard was proposed by the Ministry of Posts and Telecommunications of the People's Republic of China. This standard is under the jurisdiction of the Telecommunications Transmission Research Institute of the Ministry of Posts and Telecommunications. This standard was drafted by the Telecommunications Transmission Research Institute of the Ministry of Posts and Telecommunications. The main drafters of this standard are Li Shoujing and Shi Xiaohui. The called station
After receiving the phase signal, it will automatically phase 2 and then automatically import the received message, and send out the "phase confirmation" signal at the same time
After receiving the "stop" signal, transfer the line to the telephone
After picking up the phone, contacting or sending the "waiting to receive" signal, if a "stop" signal is received from the calling station, the line will be transferred to the telephone
The call is completed, and states 2 and 3 are repeated
After receiving the "stop" signal, the phone is shut down and the line is transferred to the telephone
Confirm the reception situation
The call is completed and the phone is hung up1 Original size
Use the B4 (186mm×263mm) size of GB148. B3.2 Scanning direction
The scanning point of the transmitter and receiver moves from left to right on the original or recording surface, and the scanning lines are adjacent from top to bottom, that is, the scanning point starts from the upper left corner of the scanning field and ends at its lower right corner. B3.3 Scanning parameters
B3.3.1 The cooperation factor is 829±8.3 (the corresponding cooperation index is 264±2.64). B3.3.2 The total length of the scanning line is 191.2mm (allowed to be extended to 195mm). B3.3.3 The scanning density is 4.33 lines/mm
B3.3.4 The scanning line frequency is 360 lines/min.
During the transmission process, the scanning line frequency deviation should be kept within ±10X10-6. B3.4 Effective transmission area
The effective transmission area is not less than 165mm×250mm. B3.5 Phase
Phase before message transmission. The duration of the transmitter sending the phase signal is 6~7s. The signal structure is shown in Figure B1. The carrier start point is located at the trailing edge of the C signal, and the receiver phases at the trailing edge of the C signal. The distance between the trailing edge of the C signal and the center of the empty segment is 2%~3% of the total length of the scan line. The receiver phase deviation does not exceed ±2% of the total length of the scan line. For the signal ~75 and when 1% - Scan or:
Figure B1 Phase signal structure
A-send a carrier with a 0° phase during 94% to 96% of the total length of the scan line; B-send a carrier with a 180° phase for the same time length as A; C-no signal during the remaining 6% to 4% of the total length of the scan line (the level is at least 26dB lower than the intervals A and B)7
B3.6 Reference signal
GB/T2886-92
During the message transmission, the transmitter should send a full-amplitude carrier at the position equivalent to the above C signal. At the end of this signal, the carrier phase should be converted by 180°. The receiver can use this signal as a reference for amplitude and phase, and indicate that the message is still being transmitted. B3.7 Modulation and demodulation
B3.7.1 Use residual sideband amplitude modulation-phase modulation. The carrier frequency is 2250±2Hz. The white signal is represented by a full-amplitude carrier, and the black signal is represented by no carrier or a carrier with an amplitude at least 26dB lower than the white signal. The phase of the black signal changes by 180° each time. If a halftone image with a limited number of levels is transmitted, different colors are distinguished by different carrier amplitudes. B3.7.2 The residual sideband filter is placed in the transmitter. The relative transmission coefficient of the filter at the carrier frequency should be 0.5, with a deviation of ±0.05. The frequency characteristic should be odd-symmetrical to the carrier frequency within the frequency range of 1500 to 3000Hz, and the odd-symmetrical deviation should be within ±10%. The group delay distortion within the frequency range of 500 to 3000Hz is not greater than 500μs. B3.7.3 The receiver can still work normally when the carrier frequency deviates from the nominal value by ±16Hz. B3.7.4 The receiver can be set with an amplitude equalizer as needed. B3.8 Transmitter output level
The white signal level adjustment range of the transmitter output to the line is -15 to 0dBm. The black signal level should be at least 26dB lower than the white signal level.
B3.9 Receiver input level
Receiver input level (white signal) should be able to work normally within the range of 0～
B3.10 Coordination between fax machine and telephone circuit
-40dBm, and its sensitivity does not need to be adjusted manually. B3.10.1 Fax machines used in telephone exchange networks should have network controllers that can be used alternately with telephones. Fax machines used on dedicated circuits should have the performance of 2-wire or 4-wire access. B3.10.2 The output impedance of the transmitter and the input impedance of the receiver are 600±100Q (balanced) in the frequency band of 500～3000Hz.
B3.10.3 The receiver should be able to work normally when the signal-to-noise ratio is not less than 13dB. Note: The signal-to-noise ratio refers to the ratio of the white signal power to the non-weighted value of the white noise power in the 300～3400Hz band. B3.11 Control
The receiver sends a "waiting" signal, indicating that the receiver is in the receiving state, and its duration is 3 to 6 seconds. Sending a "phase confirmation" signal indicates that the receiver has completed the phase, and there should be an indication on the transmitter. Either the transmitter or the receiver sends a "stop" signal, and there should be an indication on the other party's fax machine to indicate that the fax transmission needs to be interrupted and a telephone connection needs to be established.
The above control signals are all 600±10Hz continuous sinusoidal signals, and their levels are the same as the fax signal levels. Manually operated fax machines must comply with the operating procedures in the following table. Automatically operated fax machines should be able to communicate with manually operated fax machines. Manual operation procedure
Status and function
0. Before establishing the circuit
1. Establishing the circuit
2. Notifying the message
Calling station
The line is connected to the telephone
The operator prepares to send the message, picks up the phone, dials and listens to the ringback tone
Hears the "waiting to receive" signal on the telephone
Signal direction
Called station
The line is connected to the telephone
Hear the ringing tone
Transfer the line to the fax machine, start the receiver, and send out the "waiting to receive" signal at the same time
Status and function
3. Fax transmission
4. During fax transmission, the host
calls the station
5. During fax transmission, the receiver
calls the station
6. Telephone contact (receiving state 1)
7. Fax transmission
8. Call the called station
9. Receive confirmation and end transmission
10. Disconnect
GB/T2886—92
Calling station
Receive the "waiting to receive" signal, transfer the line to the fax machine, start the transmitter, send out the phase signal, and then automatically import the transmission message after 6~7s. Receive the "phase confirmation" signal
Send the "stop" signal and transfer the line to the telephone
Receive the "stop" signal Signal, transfer the line to the telephone
Telephone contact or after listening to the "waiting to receive" signal, if you still need to contact, send the "stop" signal
Conversation completed, repeat state 2 and 3
Transmission completed, stop, send the "stop" signal, and transfer the line to the telephone
Notify that the message has been sent
Conversation ended, hang up
Note: 1) The receiving end sends a ringing tone to the receiving station and a ringback tone to the calling station. Signal direction
2) For equipment that can transmit multiple pages continuously, the adjacent pages can be re-aligned when necessary. Additional remarks:
This standard was proposed by the Ministry of Posts and Telecommunications of the People's Republic of China. This standard is under the jurisdiction of the Telecommunications Transmission Research Institute of the Ministry of Posts and Telecommunications. This standard was drafted by the Telecommunications Transmission Research Institute of the Ministry of Posts and Telecommunications. The main drafters of this standard are Li Shoujing and Shi Xiaohui. The called station
After receiving the phase signal, it will automatically phase 2 and then automatically import the received message, and send out the "phase confirmation" signal at the same time
After receiving the "stop" signal, transfer the line to the telephone
After picking up the phone, contacting or sending the "waiting to receive" signal, if a "stop" signal is received from the calling station, the line will be transferred to the telephone
The call is completed, and states 2 and 3 are repeated
After receiving the "stop" signal, the phone is shut down and the line is transferred to the telephone
Confirm the reception situation
The call is completed and the phone is hung up1 Original size
Use the B4 (186mm×263mm) size of GB148. B3.2 Scanning direction
The scanning point of the transmitter and receiver moves from left to right on the original or recording surface, and the scanning lines are adjacent from top to bottom, that is, the scanning point starts from the upper left corner of the scanning field and ends at its lower right corner. B3.3 Scanning parameters
B3.3.1 The cooperation factor is 829±8.3 (the corresponding cooperation index is 264±2.64). B3.3.2 The total length of the scanning line is 191.2mm (allowed to be extended to 195mm). B3.3.3 The scanning density is 4.33 lines/mm
B3.3.4 The scanning line frequency is 360 lines/min.
During the transmission process, the scanning line frequency deviation should be kept within ±10X10-6. B3.4 Effective transmission area
The effective transmission area is not less than 165mm×250mm. B3.5 Phase
Phase before message transmission. The duration of the transmitter sending the phase signal is 6~7s. The signal structure is shown in Figure B1. The carrier start point is located at the trailing edge of the C signal, and the receiver phases at the trailing edge of the C signal. The distance between the trailing edge of the C signal and the center of the empty segment is 2%~3% of the total length of the scan line. The receiver phase deviation does not exceed ±2% of the total length of the scan line. For the signal ~75 and when 1% - Scan or:
Figure B1 Phase signal structure
A-send a carrier with a 0° phase during 94% to 96% of the total length of the scan line; B-send a carrier with a 180° phase for the same time length as A; C-no signal during the remaining 6% to 4% of the total length of the scan line (the level is at least 26dB lower than the intervals A and B)7
B3.6 Reference signal
GB/T2886-92
During the message transmission, the transmitter should send a full-amplitude carrier at the position equivalent to the above C signal. At the end of this signal, the carrier phase should be converted by 180°. The receiver can use this signal as a reference for amplitude and phase, and indicate that the message is still being transmitted. B3.7 Modulation and demodulation
B3.7.1 Use residual sideband amplitude modulation-phase modulation. The carrier frequency is 2250±2Hz. The white signal is represented by a full-amplitude carrier, and the black signal is represented by no carrier or a carrier with an amplitude at least 26dB lower than the white signal. The phase of the black signal changes by 180° each time. If a halftone image with a limited number of levels is transmitted, different colors are distinguished by different carrier amplitudes. B3.7.2 The residual sideband filter is placed in the transmitter. The relative transmission coefficient of the filter at the carrier frequency should be 0.5, with a deviation of ±0.05. The frequency characteristic should be odd-symmetrical to the carrier frequency within the frequency range of 1500 to 3000Hz, and the odd-symmetrical deviation should be within ±10%. The group delay distortion within the frequency range of 500 to 3000Hz is not greater than 500μs. B3.7.3 The receiver can still work normally when the carrier frequency deviates from the nominal value by ±16Hz. B3.7.4 The receiver can be set with an amplitude equalizer as needed. B3.8 Transmitter output level
The white signal level adjustment range of the transmitter output to the line is -15 to 0dBm. The black signal level should be at least 26dB lower than the white signal level.
B3.9 Receiver input level
Receiver input level (white signal) should be able to work normally within the range of 0～
B3.10 Coordination between fax machine and telephone circuit
-40dBm, and its sensitivity does not need to be adjusted manually. B3.10.1 Fax machines used in telephone exchange networks should have network controllers that can be used alternately with telephones. Fax machines used on dedicated circuits should have the performance of 2-wire or 4-wire access. B3.10.2 The output impedance of the transmitter and the input impedance of the receiver are 600±100Q (balanced) in the frequency band of 500～3000Hz.
B3.10.3 The receiver should be able to work normally when the signal-to-noise ratio is not less than 13dB. Note: The signal-to-noise ratio refers to the ratio of the white signal power to the non-weighted value of the white noise power in the 300～3400Hz band. B3.11 Control
The receiver sends a "waiting" signal, indicating that the receiver is in the receiving state, and its duration is 3 to 6 seconds. Sending a "phase confirmation" signal indicates that the receiver has completed the phase, and there should be an indication on the transmitter. Either the transmitter or the receiver sends a "stop" signal, and there should be an indication on the other party's fax machine to indicate that the fax transmission needs to be interrupted and a telephone connection needs to be established.
The above control signals are all 600±10Hz continuous sinusoidal signals, and their levels are the same as the fax signal levels. Manually operated fax machines must comply with the operating procedures in the following table. Automatically operated fax machines should be able to communicate with manually operated fax machines. Manual operation procedure
Status and function
0. Before establishing the circuit
1. Establishing the circuit
2. Notifying the message
Calling station
The line is connected to the telephone
The operator prepares to send the message, picks up the phone, dials and listens to the ringback tone
Hears the "waiting to receive" signal on the telephone
Signal direction
Called station
The line is connected to the telephone
Hear the ringing tone
Transfer the line to the fax machine, start the receiver, and send out the "waiting to receive" signal at the same time
Status and function
3. Fax transmission
4. During fax transmission, the host
calls the station
5. During fax transmission, the receiver
calls the station
6. Telephone contact (receiving state 1)
7. Fax transmission
8. Call the called station
9. Receive confirmation and end transmission
10. Disconnect
GB/T2886—92
Calling station
Receive the "waiting to receive" signal, transfer the line to the fax machine, start the transmitter, send out the phase signal, and then automatically import the transmission message after 6~7s. Receive the "phase confirmation" signal
Send the "stop" signal and transfer the line to the telephone
Receive the "stop" signal Signal, transfer the line to the telephone
Telephone contact or after listening to the "waiting to receive" signal, if you still need to contact, send the "stop" signal
Conversation completed, repeat state 2 and 3
Transmission completed, stop, send the "stop" signal, and transfer the line to the telephone
Notify that the message has been sent
Conversation ended, hang up
Note: 1) The receiving end sends a ringing tone to the receiving station and a ringback tone to the calling station. Signal direction
2) For equipment that can transmit multiple pages continuously, the adjacent pages can be re-aligned when necessary. Additional remarks:
This standard was proposed by the Ministry of Posts and Telecommunications of the People's Republic of China. This standard is under the jurisdiction of the Telecommunications Transmission Research Institute of the Ministry of Posts and Telecommunications. This standard was drafted by the Telecommunications Transmission Research Institute of the Ministry of Posts and Telecommunications. The main drafters of this standard are Li Shoujing and Shi Xiaohui. The called station
After receiving the phase signal, it will automatically phase 2 and then automatically import the received message, and send out the "phase confirmation" signal at the same time
After receiving the "stop" signal, transfer the line to the telephone
After picking up the phone, contacting or sending the "waiting to receive" signal, if a "stop" signal is received from the calling station, the line will be transferred to the telephone
The call is completed, and states 2 and 3 are repeated
After receiving the "stop" signal, the phone is shut down and the line is transferred to the telephone
Confirm the reception situation
The call is completed and the phone is hung up
Figure B1 Phase signal structure
A-send a carrier with a 0° phase for 94% to 96% of the total length of the scan line; B-send a carrier with a 180° phase for the same time length as A; C-no signal for the remaining 6% to 4% of the total length of the scan line (the level is at least 26dB lower than the intervals A and B)7
B3.6 Reference signal
GB/T2886-92
During the message transmission, the transmitter should send a full-amplitude carrier at the position equivalent to the above C signal. The carrier phase should be converted by 180° at the end of this signal. The receiver can use this signal as a reference for amplitude and phase, and indicate that the message is still being transmitted. B3.7 Modulation and demodulation
B3.7.1 Use residual sideband amplitude modulation-phase modulation. The carrier frequency is 2250±2Hz. The white signal is represented by a full-amplitude carrier, and the black signal is represented by no carrier or a carrier with an amplitude at least 26dB lower than the white signal. The phase of the black signal is shifted by 180° each time. If a halftone image of a limited number of levels is transmitted, different colors are distinguished by different carrier amplitudes. B3.7.2 The residual sideband filter is placed in the transmitter. The relative transmission coefficient of the filter at the carrier frequency should be 0.5, with a deviation of ±0.05. The frequency characteristic should be odd-symmetrical to the carrier frequency in the frequency range of 1500-3000Hz, and the odd-symmetrical deviation should be within ±10%. The group delay distortion in the frequency band of 500-3000Hz is not greater than 500μs. B3.7.3 The receiver can still work normally when the carrier frequency deviates from the nominal value by ±16Hz. B3.7.4 The receiver can be set with an amplitude equalizer as needed. B3.8 Transmitter output level
The white signal level adjustment range of the transmitter output to the line is -15~0dBm. The black signal level should be at least 26dB lower than the white signal level.
B3.9 Receiver input level
Receiver input level (white signal) should be able to work normally within the range of 0～
B3.10 Coordination between fax machine and telephone circuit
-40dBm, and its sensitivity does not need to be adjusted manually. B3.10.1 Fax machines used in telephone exchange networks should have network controllers that can be used alternately with telephones. Fax machines used on dedicated circuits should have the performance of 2-wire or 4-wire access. B3.10.2 The output impedance of the transmitter and the input impedance of the receiver are 600±100Q (balanced) in the frequency band of 500～3000Hz.
B3.10.3 The receiver should be able to work normally when the signal-to-noise ratio is not less than 13dB. Note: The signal-to-noise ratio refers to the ratio of the white signal power to the non-weighted value of the white noise power in the 300～3400Hz band. B3.11 Control
The receiver sends a "waiting" signal, indicating that the receiver is in the receiving state, and its duration is 3 to 6 seconds. Sending a "phase confirmation" signal indicates that the receiver has completed the phase, and there should be an indication on the transmitter. Either the transmitter or the receiver sends a "stop" signal, and there should be an indication on the other party's fax machine to indicate that the fax transmission needs to be interrupted and a telephone connection needs to be established.
The above control signals are all 600±10Hz continuous sinusoidal signals, and their levels are the same as the fax signal levels. Manually operated fax machines must comply with the operating procedures in the following table. Automatically operated fax machines should be able to communicate with manually operated fax machines. Manual operation procedure
Status and function
0. Before establishing the circuit
1. Establishing the circuit
2. Notifying the message
Calling station
The line is connected to the telephone
The operator prepares to send the message, picks up the phone, dials and listens to the ringback tone
Hears the "waiting to receive" signal on the telephone
Signal direction
Called station
The line is connected to the telephone
Hear the ringing tone
Transfer the line to the fax machine, start the receiver, and send out the "waiting to receive" signal at the same time
Status and function
3. Fax transmission
4. During fax transmission, the host
calls the station
5. During fax transmission, the receiver
calls the station
6. Telephone contact (receiving state 1)
7. Fax transmission
8. Call the called station
9. Receive confirmation and end transmission
10. Disconnect
GB/T2886—92
Calling station
Receive the "waiting to receive" signal, transfer the line to the fax machine, start the transmitter, send out the phase signal, and then automatically import the transmission message after 6~7s. Receive the "phase confirmation" signal
Send the "stop" signal and transfer the line to the telephone
Receive the "stop" signal Signal, transfer the line to the telephone
Telephone contact or after listening to the "waiting to receive" signal, if you still need to contact, send the "stop" signal
Conversation completed, repeat state 2 and 3
Transmission completed, stop, send the "stop" signal, and transfer the line to the telephone
Notify that the message has been sent
Conversation ended, hang up
Note: 1) The receiving end sends a ringing tone to the receiving station and a ringback tone to the calling station. Signal direction
2) For equipment that can transmit multiple pages continuously, the adjacent pages can be re-aligned when necessary. Additional remarks:
This standard was proposed by the Ministry of Posts and Telecommunications of the People's Republic of China. This standard is under the jurisdiction of the Telecommunications Transmission Research Institute of the Ministry of Posts and Telecommunications. This standard was drafted by the Telecommunications Transmission Research Institute of the Ministry of Posts and Telecommunications. The main drafters of this standard are Li Shoujing and Shi Xiaohui. The called station
After receiving the phase signal, it will automatically phase 2 and then automatically import the received message, and send out the "phase confirmation" signal at the same time
After receiving the "stop" signal, transfer the line to the telephone
After picking up the phone, contacting or sending the "waiting to receive" signal, if a "stop" signal is received from the calling station, the line will be transferred to the telephone
The call is completed, and states 2 and 3 are repeated
After receiving the "stop" signal, the phone is shut down and the line is transferred to the telephone
Confirm the reception situation
The call is completed and the phone is hung up
Figure B1 Phase signal structure
A-send a carrier with a 0° phase for 94% to 96% of the total length of the scan line; B-send a carrier with a 180° phase for the same time length as A; C-no signal for the remaining 6% to 4% of the total length of the scan line (the level is at least 26dB lower than the intervals A and B)7
B3.6 Reference signal
GB/T2886-92
During the message transmission, the transmitter should send a full-amplitude carrier at the position equivalent to the above C signal. The carrier phase should be converted by 180° at the end of this signal. The receiver can use this signal as a reference for amplitude and phase, and indicate that the message is still being transmitted. B3.7 Modulation and demodulation
B3.7.1 Use residual sideband amplitude modulation-phase modulation. The carrier frequency is 2250±2Hz. The white signal is represented by a full-amplitude carrier, and the black signal is represented by no carrier or a carrier with an amplitude at least 26dB lower than the white signal. The phase of the black signal is shifted by 180° each time. If a halftone image of a limited number of levels is transmitted, different colors are distinguished by different carrier amplitudes. B3.7.2 The residual sideband filter is placed in the transmitter. The relative transmission coefficient of the filter at the carrier frequency should be 0.5, with a deviation of ±0.05. The frequency characteristic should be odd-symmetrical to the carrier frequency in the frequency range of 1500-3000Hz, and the odd-symmetrical deviation should be within ±10%. The group delay distortion in the frequency band of 500-3000Hz is not greater than 500μs. B3.7.3 The receiver can still work normally when the carrier frequency deviates from the nominal value by ±16Hz. B3.7.4 The receiver can be set with an amplitude equalizer as needed. B3.8 Transmitter output level
The white signal level adjustment range of the transmitter output to the line is -15~0dBm. The black signal level should be at least 26dB lower than the white signal level.
B3.9 Receiver input level
Receiver input level (white signal) should be able to work normally within the range of 0～
B3.10 Coordination between fax machine and telephone circuit
-40dBm, and its sensitivity does not need to be adjusted manually. B3.10.1 Fax machines used in telephone exchange networks should have network controllers that can be used alternately with telephones. Fax machines used on dedicated circuits should have the performance of 2-wire or 4-wire access. B3.10.2 The output impedance of the transmitter and the input impedance of the receiver are 600±100Q (balanced) in the frequency band of 500～3000Hz.
B3.10.3 The receiver should be able to work normally when the signal-to-noise ratio is not less than 13dB. Note: The signal-to-noise ratio refers to the ratio of the white signal power to the non-weighted value of the white noise power in the 300～3400Hz band. B3.11 Control
The receiver sends a "waiting" signal, indicating that the receiver is in the receiving state, and its duration is 3 to 6 seconds. Sending a "phase confirmation" signal indicates that the receiver has completed the phase, and there should be an indication on the transmitter. Either the transmitter or the receiver sends a "stop" signal, and there should be an indication on the other party's fax machine to indicate that the fax transmission needs to be interrupted and a telephone connection needs to be established.
The above control signals are all 600±10Hz continuous sinusoidal signals, and their levels are the same as the fax signal levels. Manually operated fax machines must comply with the operating procedures in the following table. Automatically operated fax machines should be able to communicate with manually operated fax machines. Manual operation procedure
Status and function
0. Before establishing the circuit
1. Establishing the circuit
2. Notifying the message
Calling station
The line is connected to the telephone
The operator prepares to send the message, picks up the phone, dials and listens to the ringback tone
Hears the "waiting to receive" signal on the telephone
Signal direction
Called station
The line is connected to the telephone
Hear the ringing tone
Transfer the line to the fax machine, start the receiver, and send out the "waiting to receive" signal at the same time
Status and function
3. Fax transmission
4. During fax transmission, the host
calls the station
5. During fax transmission, the receiver
calls the station
6. Telephone contact (receiving state 1)
7. Fax transmission
8. Call the called station
9. Receive confirmation and end transmission
10. Disconnect
GB/T2886—92
Calling station
Receive the "waiting to receive" signal, transfer the line to the fax machine, start the transmitter, send out the phase signal, and then automatically import the transmission message after 6~7s. Receive the "phase confirmation" signal
Send the "stop" signal and transfer the line to the telephone
Receive the "stop" signal Signal, transfer the line to the telephone
Telephone contact or after listening to the "waiting to receive" signal, if you still need to contact, send the "stop" signal
Conversation completed, repeat state 2 and 3
Transmission completed, stop, send the "stop" signal, and transfer the line to the telephone
Notify that the message has been sent
Conversation ended, hang up
Note: 1) The receiving end sends a ringing tone to the receiving station and a ringback tone to the calling station. Signal direction
2) For equipment that can transmit multiple pages continuously, the adjacent pages can be re-aligned when necessary. Additional remarks:
This standard was proposed by the Ministry of Posts and Telecommunications of the People's Republic of China. This standard is under the jurisdiction of the Telecommunications Transmission Research Institute of the Ministry of Posts and Telecommunications. This standard was drafted by the Telecommunications Transmission Research Institute of the Ministry of Posts and Telecommunications. The main drafters of this standard are Li Shoujing and Shi Xiaohui. The called station
After receiving the phase signal, it will automatically phase 2 and then automatically import the received message, and send out the "phase confirmation" signal at the same time
After receiving the "stop" signal, transfer the line to the telephone
After picking up the phone, contacting or sending the "waiting to receive" signal, if a "stop" signal is received from the calling station, the line will be transferred to the telephone
The call is completed, and states 2 and 3 are repeated
After receiving the "stop" signal, the phone is shut down and the line is transferred to the telephone
Confirm the reception situation
The call is completed and the phone is hung up11 Control
The receiver sends out a "waiting to receive" signal, indicating that the receiver is in the receiving state, which lasts for 3 to 6 seconds. Send out a "phase confirmation" signal, indicating that the receiver has completed the phase, and there should be an indication on the transmitter. If either the transmitter or the receiver sends out a "stop" signal, there should be an indication on the other party's fax machine to indicate that the fax transmission needs to be interrupted and a telephone connection needs to be established.
The above control signals are all 600±10Hz continuous sinusoidal signals, and their levels are the same as the fax signal levels. Manually operated fax machines must comply with the operating procedures in the following table. Automatically operated fax machines should be able to communicate with manually operated fax machines. Manual operation procedure
Status and function
0. Before establishing the circuit
1. Establishing the circuit
2. Notifying the message
Calling station
The line is connected to the telephone
The operator prepares to send the message, picks up the phone, dials and listens to the ringback tone
Hears the "waiting to receive" signal on the telephone
Signal direction
Called station
The line is connected to the telephone wwW.bzxz.Net
Hear the ringing tone
Transfer the line to the fax machine, start the receiver, and send out the "waiting to receive" signal at the same time
Status and function
3. Fax transmission
4. During fax transmission, the host
calls the station
5. During fax transmission, the receiver
calls the station
6. Telephone contact (receiving state 1)
7. Fax transmission
8. Call the called station
9. Receive confirmation and end transmission
10. Disconnect
GB/T2886—92
Calling station
Receive the "waiting to receive" signal, transfer the line to the fax machine, start the transmitter, send out the phase signal, and then automatically import the transmission message after 6~7s. Receive the "phase confirmation" signal
Send the "stop" signal and transfer the line to the telephone
Receive the "stop" signal Signal, transfer the line to the telephone
Telephone contact or after listening to the "waiting to receive" signal, if you still need to contact, send the "stop" signal
Conversation completed, repeat state 2 and 3
Transmission completed, stop, send the "stop" signal, and transfer the line to the telephone
Notify that the message has been sent
Conversation ended, hang up
Note: 1) The receiving end sends a ringing tone to the receiving station and a ringback tone to the calling station. Signal direction
2) For equipment that can transmit multiple pages continuously, the adjacent pages can be re-aligned when necessary. Additional remarks:
This standard was proposed by the Ministry of Posts and Telecommunications of the People's Republic of China. This standard is under the jurisdiction of the Telecommunications Transmission Research Institute of the Ministry of Posts and Telecommunications. This standard was drafted by the Telecommunications Transmission Research Institute of the Ministry of Posts and Telecommunications. The main drafters of this standard are Li Shoujing and Shi Xiaohui. The called station
After receiving the phase signal, it will automatically phase 2 and then automatically import the received message, and send out the "phase confirmation" signal at the same time
After receiving the "stop" signal, transfer the line to the telephone
After picking up the phone, contacting or sending the "waiting to receive" signal, if a "stop" signal is received from the calling station, the line will be transferred to the telephone
The call is completed, and states 2 and 3 are repeated
After receiving the "stop" signal, the phone is shut down and the line is transferred to the telephone
Confirm the reception
The call is completed and the phone is hung up11 Control
The receiver sends out a "waiting to receive" signal, indicating that the receiver is in the receiving state, which lasts for 3 to 6 seconds. Send out a "phase confirmation" signal, indicating that the receiver has completed the phase, and there should be an indication on the transmitter. If either the transmitter or the receiver sends out a "stop" signal, there should be an indication on the other party's fax machine to indicate that the fax transmission needs to be interrupted and a telephone connection needs to be established.
The above control signals are all 600±10Hz continuous sinusoidal signals, and their levels are the same as the fax signal levels. Manually operated fax machines must comply with the operating procedures in the following table. Automatically operated fax machines should be able to communicate with manually operated fax machines. Manual operation procedure
Status and function
0. Before establishing the circuit
1. Establishing the circuit
2. Notifying the message
Calling station
The line is connected to the telephone
The operator prepares to send the message, picks up the phone, dials and listens to the ringback tone
Hears the "waiting to receive" signal on the telephone
Signal direction
Called station
The line is connected to the telephone
Hear the ringing tone
Transfer the line to the fax machine, start the receiver, and send out the "waiting to receive" signal at the same time
Status and function
3. Fax transmission
4. During fax transmission, the host
calls the station
5. During fax transmission, the receiver
calls the station
6. Telephone contact (receiving state 1)
7. Fax transmission
8. Call the called station
9. Receive confirmation and end transmission
10. Disconnect
GB/T2886—92
Calling station
Receive the "waiting to receive" signal, transfer the line to the fax machine, start the transmitter, send out the phase signal, and then automatically import the transmission message after 6~7s. Receive the "phase confirmation" signal
Send the "stop" signal and transfer the line to the telephone
Receive the "stop" signal Signal, transfer the line to the telephone
Telephone contact or after listening to the "waiting to receive" signal, if you still need to contact, send the "stop" signal
Conversation completed, repeat state 2 and 3
Transmission completed, stop, send the "stop" signal, and transfer the line to the telephone
Notify that the message has been sent
Conversation ended, hang up
Note: 1) The receiving end sends a ringing tone to the receiving station and a ringback tone to the calling station. Signal direction
2) For equipment that can transmit multiple pages continuously, the adjacent pages can be re-aligned when necessary. Additional remarks:
This standard was proposed by the Ministry of Posts and Telecommunications of the People's Republic of China. This standard is under the jurisdiction of the Telecommunications Transmission Research Institute of the Ministry of Posts and Telecommunications. This standard was drafted by the Telecommunications Transmission Research Institute of the Ministry of Posts and Telecommunications. The main drafters of this standard are Li Shoujing and Shi Xiaohui. The called station
After receiving the phase signal, it will automatically phase 2 and then automatically import the received message, and send out the "phase confirmation" signal at the same time
After receiving the "stop" signal, transfer the line to the telephone
After picking up the phone, contacting or sending the "waiting to receive" signal, if a "stop" signal is received from the calling station, the line will be transferred to the telephone
The call is completed, and states 2 and 3 are repeated
After receiving the "stop" signal, the phone is shut down and the line is transferred to the telephone
Confirm the reception
The call is completed and the phone is hung up
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