tfra08c13 ETC-unknow, tfra08c13 Datasheet - Page 46

• Manufacturer Part Number: tfra08c13
• Description: Tfra08c13 Octal T1/e1 Framer
• Manufacturer: ETC-unknow

TFRA08C13 OCTAL T1/E1 Framer
Frame Formats
CEPT 2.048 Basic Frame Structure
The ITU Rec. G.704 Section 2.3.1 defined frame length is 256 bits, numbered 1 to 256. The frame repetition rate is
8 kHz. The allocation of bits numbered 1 to 8 of the frame is shown in Table 19.
Table 19. Allocation of Bits 1 to 8 of the FAS Frame and the NOT FAS Frame
The function of each bit in Table 19 is described below:
46
Frame Alignment Signal (FAS)
Not Frame Alignment Signal
(NOT FAS)
The Si bits are reserved for international use. A specific use for these bits is described in Table 20. ITU CRC-4
Multiframe Structure. If no use is realized, these bits should be fixed at 1 on digital paths crossing an interna-
tional border.
Bit 2 of the NOT FAS frames is fixed to 1 to assist in avoiding simulations of the frame alignment signal.
Bit 3 of the NOT FAS is the remote alarm indication (A bit). In undisturbed operation, this bit is set to 0; in alarm
condition, set to 1.
Bits 4—8 of the NOT FAS (Sa4—Sa8) may be recommended by ITU for use in specific point-to-point applica-
tions. Bit Sa4 may be used as a message-based data link for operations, maintenance, and performance moni-
toring. If the data link is accessed at intermediate points with consequent alterations to the Sa4 bit, the CRC-4
bits must be updated to retain the correct end-to-end path termination functions associated with the CRC-4 pro-
cedure. The receive framer does not implement the CRC-4 modifying algorithm described in ITU Rec. G.706
Annex C. Bits Sa4—Sa8, where these are not used, should be set to 1 on links crossing an international border.
MSB = most significant bit and is transmitted first.
LSB = least significant bit and is transmitted last.
Basic Frames
(continued)
Bit 1 (MSB)
Si
Si
Bit 2
0
1
Bit 3
A
0
Bit 4
Sa4
1
Bit 5
Sa5
1
Preliminary Data Sheet
Bit 6
Sa6
0
Lucent Technologies Inc.
Lucent Technologies Inc.
Bit 7
Sa7
1
October 2000
Bit 8 (LSB)
Sa8
1