TS-16 in E1 Multi Frame Structuret

TS-16 in E1 Multi Frame Structuret
- Common Channel Signaling (CCS) ? at least one channel (usually TS16) is used for

signaling and serves asynchronously all the channels
- Channel Associated Signaling (CAS) ? in each multi-frame, for each channel, there is a

frame that half of it?s TS16, is dedicated for that channel signaling:
- Frame 0 is used for alarm indication and spare bits
- Frame 1 is used for channels 1 and 16 (4 bits each)
- Frame 2 is used for channels 2 and 17 (4 bits each)
- ?
- Frame 15 is used for channels 15 and 30 (4 bits each)

- When the bits aren?t used for signaling 2nd and 4th bits should be ?1? and the 3rd

should be ?0?.
- The bits can be used for signaling of 2 states (1 bit), 4 states (2 bits) or 15 states

(4 bits minus ?0000?).
- This was used mainly to the on-off-keying slow dial method (OOK). Today DTMF is used

in each data channel as part of the data

E1 Multi Frame Structure

E1 Multi Frame Structure
- A multi-frame is formed from consecutive 16 frames numbered 0-15
- It is used for adding information regarding the data:
- In TS0 ? synchronization between frames & Error Correcting
- In TS16 ? Signaling

TS-0 in E1 Multi Frame Structure
- Synchronization is gained in every 2nd frame. The synchronization pattern is 0011011.
Specifically in the even numbered frames (0, 2?) bits 1-7 (from 0-7) holds the mentioned

pattern.
- Note that this synchronization does not involves a clock, but bits are transmitted

constantly even when the line is idle.
- Error correcting (optional) is done using a Cyclic Redundancy Check (CRC-4) that uses

4 bits for every half multi-frame (8 frames). specifically the 4 bits are placed in bit

0 of every 2nd (even) frame, before the synchronization pattern.
- Error indication bits using CRC-4 are held in frames 13 and 15
- Remote alarm indication bit is held in bit 3 of odd numbered frames (1, 3?)
- Other bits in the odd frames are spare bits.