E1, Time slot 15 or 17 which one is use for signaling

[kayih]

I'm reading the CVOICE student guide, in section 2, they explain that timeslot 17 is use for carrying CAS E1 (channel associated signaling) signalisation for other timeslot.

In my BCRAN book, it is said that timeslot 15 is used for canal D signalisation.

So my question is, how many timeslot are used for signaling when configuring E1 interface.

thanks

[mheusinger]

Hello,

there is always some confusion about the exact number, because there are (at least?) two ways used to count time slots in an E1.

The most common way is to start with 0 and number the TS up to 31. In this case TS0 is used for framing and TS16 is used for CAS/CCS signaling in a voice environment.

The second way is to start counting with 1 up to 32 (used f.e. in some Cisco WAN switches). Then TS1 is used for framing and TS17 is used for signaling.

So the first TS of the "lower half 16 TS" is used for framing and the first TS of the "upper half 16 TS" is used for voice signaling.

I am not aware that TS15 would be used for CAS signaling in a usual environment.

So please check, whether there is any indication about the system used for numbering the TS.

Hope this helps! Please rate all posts.

Regards, Martin

[prabhmitkaur]

Hi

Though you have givena ver nice answer, still i would like to clarify one thing....I had always known that in case of CAS theer is no separate channel for signalling. IT uses robbed bit concept.

So how can TS15 be used for CAS signalling as mentioned by you.

Plz.suggest.