This standard specifies the technical indicators and functions of 4×139264kbit/s optical terminals used in optical cable digital line systems in my country's public telecommunications network (including technical indicators of optical and electrical interfaces, functions required for maintenance and use, environmental conditions, etc.). It is the technical basis for the design and production of 4×139264kbit/s optical terminals. This standard applies to 4×139264kbit/s optical terminals used in long-distance optical cable digital line systems and intra-city inter-office relay optical cable communication systems. GB/T 15840-1995 Technical requirements for 4×139264kbit/s optical terminals GB/T15840-1995 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Technical requirement for optical line terminalsat4×139264kbit/s
GB/T15840—1995
This standard is based on the original International Telegraph and Telephone Consultative Committee (CCITT) recommendations G.921 "Digital segments based on the 2048kbit/s series", G.955 "Digital line system for transmitting 1554kbit/s and 2048kbit/s series signals on optical cables" and other related contents. 1 Subject content and scope of application
This standard specifies the technical indicators and functions of 4×139264kbit/s optical terminals used in optical cable digital line systems in my country's public telecommunications network (including technical indicators of optical and electrical interfaces, functions required for maintenance and use, environmental conditions, etc.). It is the technical basis for the design and production of 4×139264kbit/s optical terminals.
This standard applies to 4×139264kbit/s optical transceivers used in long-distance optical cable digital line systems and intra-city inter-office relay optical cable communication systems. 4×139264kbit/s optical transceivers used in dedicated telecommunication networks can also refer to this standard. 2 Reference standards
GB/T13997—922048kbit/s8448kbit/s.34368kbit/s, 139264kbit/s optical transceiver technical requirements 3 Optical transceiver composition and multiplexed frame structure
3.1 Optical transceiver composition
4X139264kbit/s optical transceiver combines the function of multiplexing four 139264kbit/s digital signals with the function of optical cable line transmission terminal equipment. Figure 1 shows a system in a 4×139264kbit/s optical terminal, which is mainly composed of the input interface circuit, multiplexer, optical transmitter on the sending side and the output interface circuit, demultiplexer, and optical receiver on the receiving side. Approved by the State Bureau of Technical Supervision on December 13, 1995 and implemented on June 1, 1996
In the figure: TT
4 139264
kbit/s input
4 139264
kbit/s output
GB/T15840-1995
Input interface
Input interface
Input interface
Input interface
Input interface
|Output interface
Output interface
Output interface
Output interface
Sending side
Receiving side
The four 139264.kbit/s electrical interfaces of the optical terminal are the connection points with the 139264kbit/s digital equipment; F, F—the optical interface of the optical terminal, the connection points with the optical fiber line, S—the optical fiber point behind the optical connector C of the optical transmitter, R—the optical fiber point in front of the optical connector C of the optical receiver. Figure 14 Schematic diagram of a system of a 139264kbit/s optical terminal 3.2 Multiplexing frame structure
3.2.1 Frame structure
The method of multiplexing and code rate adjustment of the four 139264kbit/s branch signals adopts the method of cyclic bit-by-bit alternating multiplexing and positive code rate adjustment in the order of branch numbering. The code rate adjustment indication bit is represented by C (n-1, 2, 3, 4, 5) and should be configured in a dispersed manner. When there is code rate adjustment, the indication bits C, C3C, and C5 are represented by "11111"; when there is no code rate adjustment, the indication bits C and C2CCC are represented by "00000". The majority decision method is adopted during detection. The multiplexing frame structure is specified in Table 1. Table 1 Multiplexing frame structure
Branch bit rate
kbit/s
Number of branches
Frame structure
Relying on positioning signal (111110100000))
Bits from each branch
-KAONIKAca-
139264
Bit number
13~384
Branch bit rate
kbit/s
Code rate adjustment indication bit Cm (n=1~ 5) 1) Bits from each branch
Alarm indication of the other end, reserved for domestic use
Branch bits that can be used for code rate adjustment
Bits from each branch
Number of bits per branch
Maximum code rate adjustment ratio per branch
Nominal code rate adjustment ratio
GB/T15840-1995
Continued Table 1
Note: 1) C represents the nth code rate adjustment indication bit of the ith branch. 3.2.2 Recovery of lost position and frame alignment
139264
Group I to Group V
2688bit
663bit
210190bit/s
When four consecutive bits have been in their predetermined positions When an erroneous frame positioning signal is received, it should be considered that a frame loss has occurred. When a frame loss is confirmed, when the frame positioning device detects the frame positioning signal for three consecutive frames, it should be judged that the frame positioning has been effectively restored. After the frame positioning device has detected a correct frame positioning signal, if the frame positioning signal is not detected in one of the following two frames, a new search for the frame positioning signal should be started. 4 Technical indicators
4.1 Electrical interface indicatorsbZxz.net
41.1 General requirements
a) Bit rate and tolerance
Nominal bit rate: 139264kbit/s
b) Code type
Difference: ±15×10-6
Code type of the signal on the electrical interface: CMI code.
c) Overvoltage protection requirements|| tt||139264kbit/s input and output ports should be able to withstand the impact of 10 standard lightning pulses (5 negative pulses and 5 positive pulses) without being damaged. The rise time of the lightning pulse is 1.2us, the width is 50us, and the amplitude is Upc-20V. When the input and output ports are connected to the coaxial cable, the connection circuit of the differential mode test pulse generator is shown in Figure 2. 233
4.1.2 Output port indicators
a) Output port waveform
GB/T15840-1995
Figure 21.2/50us differential mode voltage pulse generator output port waveform is measured at the four 139264kbit/s output port T points in Figure 1, and its waveform should comply with the relevant provisions of GB/T13997.
b) Output port return loss
The output port return loss is measured at the four 139264kbit/s output port T points in Figure 1. Its value should not be less than 15dB in the range of 7MHz to 210MHz.
c) Maximum output jitter without input jitter The maximum output jitter without input jitter measured at the four 139264kbit/s output port T points in Figure 1 should meet the relevant provisions of GB/13997.
4.1.3 Input port indicators
a) Attenuation characteristics of connecting cables
The digital signal added to the input port T of the 4×139264kbit/s optical terminal should comply with the provisions of 4.1.2a) of this standard, but it should be changed according to the characteristics of the connected coaxial line pair. Assuming that the attenuation characteristics of the coaxial line pair follow the approximate law of change, the attenuation range is 0-12dB at 70MHz
b) The lower limit of the maximum allowable input jitter
The lower limit of the maximum allowable input jitter is measured at the four 139264kbit/s input port T points in Figure 1. When the attenuation characteristics of the input port connecting cable meet the requirements of 4.1.3a) of this standard, the lower limit of the input jitter of the input port shall meet the requirements of Figure 3. The test signal is a 223-1 pseudo-random signal sequence, modulated by a sinusoidal jitter with the amplitude/frequency relationship specified in Figure 3. Peak-to-peak jitter amplitude (UI)
(18p4s)
20dB/10oct drop
Jitter frequency (logarithmic coordinates)
Figure 3 Lower limit of maximum allowable input jitter
c) Input port return loss
3500kHz
The input port return loss is measured at the four 139264kbit/s input port T points in Figure 1. Its value should not be less than 15dB in the range of 7MHz to 210MHz.
TKAonikaca-
4.1.4 Jitter transfer characteristics
GB/T15840-1995
The maximum gain of the jitter transfer characteristics should not be greater than 0.6dB. Considering the limitations of the test instrument, the lowest frequency of the jitter test can be measured to 10Hz.
4.2 Optical interface specifications
4.2.1 Average Transmitted Optical Power
4×139264kbit/s The average transmitted optical power of the optical terminal is measured at point S in Figure 1. Its value should be determined according to the length of the relay segment. When an LD light source is used, the average transmitted optical power is divided into four levels: -9dBm, -6dBm, -3dBm and 0dBm. 4.2.2 Receiver Sensitivity
Receiver sensitivity refers to the minimum received optical power measured at point R in Figure 1 when the average bit error rate (BER) is not greater than 1×10-11. Its value should meet the requirements of Table 2.
Table 24×139264kbit/s optical terminal receiver sensitivity speed
kbit/s
4X139264
4.2.3 Dynamic range
Center wavelength
1310 or 1550
Photodetector type
PIN-FET
Receiver sensitivity (BER≤1X10-1)
When the average bit error rate (BER) is not greater than 1×10-31, the dynamic range of the received optical power measured at point R in Figure 1 (the difference between the measured maximum received optical power and the measured receiver sensitivity) shall not be less than 20dB. 4.3 Line Code Type
4X139264kbit/s optical terminal line code type in addition to the 5B6B, 8B1H code type, can also use other code types approved by the competent authorities, such as NRZ scrambling code, etc.
4.4 Error Performance Requirements
4X139264kbit/s optical terminal average bit error rate BER ≤ 1 × 10-11 (continuous test time is not less than 24h). 4.5 Reliability Requirements
4×139264kbit/s optical terminal average failure time (MTBF) is not less than 5 years. 5 Maintenance and use requirements
5.1 Monitoring function
4×139264kbit/s optical terminal should have the following monitoring functions: internal power failure monitoring;
branch input signal interruption monitoring;
LD pre-bias current and receiver AGC voltage monitoring; LD life monitoring;
transmitted optical signal and received optical signal disappearance monitoring; error performance and bit error rate monitoring;
line code frame loss monitoring;
multiplexing frame loss monitoring;
opposite end alarm indication monitoring.
5.2 Alarm function
4×139264kbit/s optical terminal should have fault alarm function to facilitate maintenance of the optical terminal. Alarm items and corresponding measures are listed in Table 3.
Alarm item
Internal power failure
Branch input signal interruption
LD transmit optical signal disappears
Receive optical signal disappears
Line code frame loss
BER≥10-3
Multiplex frame loss
LD life
BER≥10-6
Detect the alarm indication of the opposite end
GB/T15840-1995
Maintenance alarm type
Alarm item and corresponding measures
Issue an alarm to the opposite end
||Alarm indication
AIS is added to
all branches
to (if possible)
the
relevant time slots of the multiplexed signal
Shelf top indication
red light, sound
red light, sound
red light, sound
red light, sound
red light, sound
red light, sound
yellow or white light
yellow or white light
Note: 1) The binary content of the alarm indication signal AIS is a series of "1". The bit rate of AIS should comply with the requirements of 4.1.1 of this standard. 5.3 Automatic protection switching function
4×139264kbit/s optical transceiver should have auxiliary channels to realize the transmission of switching control signals and main signals in the same optical fiber. The switching signal needs to have a backup transmission route.
Switching condition: an immediate alarm occurs at the receiving end of the main system, and the backup system works normally. Switching mode:
Automatic switching mode. When the switching conditions are met, the main system automatically switches to the backup system. When the main system returns to normal about 5~12 minutes later, it automatically switches from the backup system to the main system. Manual switching mode. The main system automatically switches to the backup system by manual operation, and must also be manually controlled to switch back to the main system. Automatic switching time: The sum of the transmission time of the request signal and the switching control signal and the action time of the switching switch should not exceed 50ms.
5.4 Business contact function
4×139264kbit/s optical transceiver should have two business telephones. The business telephone has the functions of site selection calling and conference calling. The business signal should be transmitted in the same optical fiber as the main signal. 6 Environmental conditions
6.1 Ambient temperature and humidity
Working ambient temperature: 5℃～40℃
Working relative humidity: ≤85% (25℃) Temperature during transportation and storage: 20℃～60℃6.2 Power supply voltage
DC--57V～-40V or DC-26.4V~-21.6V. 6.3 Earthquake resistance requirements
TKAONIKAca-
GB/T15840-1995
4×139264kbit/s optical terminal should not reduce its performance indicators after conventional vibration tests. Grounding requirements
4×139264kbit/s optical terminal working ground and protection ground should be set separately and insulated from each other. Protection against interference
The optical transceiver should be able to resist the influence of electromagnetic interference and electrostatic discharge. The optical transceiver should not affect other communication equipment during operation. 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 Science Research and Planning Institute of the Ministry of Posts and Telecommunications. This standard was drafted by the Wuhan Post and Telecommunications Science Research Institute of the Ministry of Posts and Telecommunications. The main drafters of this standard are Chen Jingxian and Song Xianzeng. 2372 Alarm function
4×139264kbit/s optical transceiver shall have fault alarm function to facilitate maintenance of the optical transceiver. Alarm items and corresponding measures are listed in Table 3.
Alarm item
Internal power failure
Branch input signal interruption
LD transmit optical signal disappears
Receive optical signal disappears
Line code frame loss
BER≥10-3
Multiplex frame loss
LD life
BER≥10-6
Detection of peer alarm indication
GB/T15840-1995
Maintenance alarm type
Alarm item and corresponding measures
Issue an alarm to the peer
|| ||Alarm indication
AIS is added to
all branches
to|(if possible)
the
relevant time slots of the multiplexed signal
Shelf top indication
red light, sound
red light, sound
red light, sound
red light, sound
red light, sound
red light, sound
yellow or white light
yellow or white light
Note: 1) The binary content of the alarm indication signal AIS is a series of "1". The bit rate of AIS should comply with the requirements of 4.1.1 of this standard. 5.3 Automatic protection switching function
4×139264kbit/s optical transceiver should have auxiliary channels to realize the transmission of switching control signals and main signals in the same optical fiber. The switching signal needs to have a backup transmission route.
Switching condition: an immediate alarm occurs at the receiving end of the main system, and the backup system works normally. Switching mode:
Automatic switching mode. When the switching conditions are met, the main system automatically switches to the backup system. When the main system returns to normal about 5~12 minutes later, it automatically switches from the backup system to the main system. Manual switching mode. The main system automatically switches to the backup system by manual operation, and must also be manually controlled to switch back to the main system. Automatic switching time: The sum of the transmission time of the request signal and the switching control signal and the action time of the switching switch should not exceed 50ms.
5.4 Business contact function
4×139264kbit/s optical transceiver should have two business telephones. The business telephone has the functions of site selection calling and conference calling. The business signal should be transmitted in the same optical fiber as the main signal. 6 Environmental conditions
6.1 Ambient temperature and humidity
Working ambient temperature: 5℃～40℃
Working relative humidity: ≤85% (25℃) Temperature during transportation and storage: 20℃～60℃6.2 Power supply voltage
DC--57V～-40V or DC-26.4V~-21.6V. 6.3 Earthquake resistance requirements
TKAONIKAca-
GB/T15840-1995
4×139264kbit/s optical terminal should not reduce its performance indicators after conventional vibration tests. Grounding requirements
4×139264kbit/s optical terminal working ground and protection ground should be set separately and insulated from each other. Protection against interference
The optical transceiver should be able to resist the influence of electromagnetic interference and electrostatic discharge. The optical transceiver should not affect other communication equipment during operation. 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 Science Research and Planning Institute of the Ministry of Posts and Telecommunications. This standard was drafted by the Wuhan Post and Telecommunications Science Research Institute of the Ministry of Posts and Telecommunications. The main drafters of this standard are Chen Jingxian and Song Xianzeng. 2372 Alarm function
4×139264kbit/s optical transceiver shall have fault alarm function to facilitate maintenance of the optical transceiver. Alarm items and corresponding measures are listed in Table 3.
Alarm item
Internal power failure
Branch input signal interruption
LD transmit optical signal disappears
Receive optical signal disappears
Line code frame loss
BER≥10-3
Multiplex frame loss
LD life
BER≥10-6
Detection of peer alarm indication
GB/T15840-1995
Maintenance alarm type
Alarm item and corresponding measures
Issue an alarm to the peer
|| ||Alarm indication
AIS is added to
all branches
to (if possible)
the
relevant time slots of the multiplexed signal
Shelf top indication
red light, sound
red light, sound
red light, sound
red light, sound
red light, sound
red light, sound
yellow or white light
yellow or white light
Note: 1) The binary content of the alarm indication signal AIS is a series of "1". The bit rate of AIS should comply with the requirements of 4.1.1 of this standard. 5.3 Automatic protection switching function
4×139264kbit/s optical transceiver should have auxiliary channels to realize the transmission of switching control signals and main signals in the same optical fiber. The switching signal needs to have a backup transmission route.
Switching condition: an immediate alarm occurs at the receiving end of the main system, and the backup system works normally. Switching mode:
Automatic switching mode. When the switching conditions are met, the main system automatically switches to the backup system. When the main system returns to normal about 5~12 minutes later, it automatically switches from the backup system to the main system. Manual switching mode. The main system automatically switches to the backup system by manual operation, and must also be manually controlled to switch back to the main system. Automatic switching time: The sum of the transmission time of the request signal and the switching control signal and the action time of the switching switch should not exceed 50ms.
5.4 Business contact function
4×139264kbit/s optical transceiver should have two business telephones. The business telephone has the functions of site selection calling and conference calling. The business signal should be transmitted in the same optical fiber as the main signal. 6 Environmental conditions
6.1 Ambient temperature and humidity
Working ambient temperature: 5℃～40℃
Working relative humidity: ≤85% (25℃) Temperature during transportation and storage: 20℃～60℃6.2 Power supply voltage
DC--57V～-40V or DC-26.4V~-21.6V. 6.3 Earthquake resistance requirements
TKAONIKAca-
GB/T15840-1995
4×139264kbit/s optical terminal should not reduce its performance indicators after conventional vibration tests. Grounding requirements
4×139264kbit/s optical terminal working ground and protection ground should be set separately and insulated from each other. Protection against interference
The optical transceiver should be able to resist the influence of electromagnetic interference and electrostatic discharge. The optical transceiver should not affect other communication equipment during operation. 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 Science Research and Planning Institute of the Ministry of Posts and Telecommunications. This standard was drafted by the Wuhan Post and Telecommunications Science Research Institute of the Ministry of Posts and Telecommunications. The main drafters of this standard are Chen Jingxian and Song Xianzeng. 237
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