[cisco-nas] SS7 signalling vs ISDN

[Lewis Watson]

> The monthly cost of SS7 Trunks are usually cheaper then ISDN trunks 
> and SS7 trunks can carry more information about the calls.
> (Such as Payphone identifier or Number of Satellite hops for the call)
> Darryl Sladden


Hi Darryl,
This brings a question to mind. What's the difference between a PRI, CAS,  and SS7. I am familiar with the fact the PRI uses the 24th channel for a "D Channel" used for timing on the other 23 B channels and that the CAS gives all 24 lines for usage and uses 8 bits per line for timing. hence  referred to as "RBS". So where does the SS7 fit in with those?

Thank you,
Lewis