Solved: CCS / CAS in-band / out-of-band

woutereelen · ‎03-20-2008

Found on wikipedia:

"Channel Associated Signaling (CAS), also known as Per-Trunk Signaling (PTS), is a form of digital communication signaling. As with most telecommunication signaling methods, it uses routing information to direct the payload of voice or data to its destination. With CAS signaling, this routing information is encoded and transmitted in the same channel as the payload itself. This information can be transmitted in the same band (in-band signaling) or a separate band (out-of-band signaling) to the payload."

I thought CAS was in-band signaling.

Do they mean with in-band and out-band the bands in the frequency spectrum?

paolo bevilacqua · ‎03-20-2008

Well, CAS with pulse dialing is actually out-of-band.

How it works, the A bit is toggled emulating the hook-switch in an analog telephone with rotary dial.

This is the only case that comes to mind, all the rest is in-band.

View solution in original post

Jaime Valencia · ‎03-20-2008

CAS means that if you have a T1 PRI you will get 24 voice calls, each DS0 contains within the same channel all the signaling for the call, that's in-band signaling

T1 PRI means you will get 23 calls, that's why it's referred ad 23B + 1D.

The D channel contains all the signaling for the other 23 channels, so it's not in the same DS0 as the voice, thus it's out of band

HTH

javalenc

if this helps, please rate

HTH

java

if this helps, please rate

paolo bevilacqua · ‎03-20-2008

Well, CAS with pulse dialing is actually out-of-band.

How it works, the A bit is toggled emulating the hook-switch in an analog telephone with rotary dial.

This is the only case that comes to mind, all the rest is in-band.

woutereelen · ‎03-20-2008

That's what I've been looking for.

I knew wikipedia wouldn't lie! :-)

Thanks p.bevilacqua.

Also thanks to the other person for answering my question, but I am familiar with CAS and CCS. I just didn't know any scenario where the signaling of CAS is send out-of-band.

br,

Wouter