Protocol

CAS / R2

Channel Associated Signaling · MFC-R2

Lab ready Full lab

Channel Associated Signaling and MFC-R2 multi-frequency compelled trunk signaling used on legacy TDM interconnects. Line signaling may be robbed-bit or dedicated bits; register signaling exchanges address digits with R2 tones. ISDN PRI and SIP have largely replaced it, but international gateways still see it.

Domains

telephony

Layers

Tags

casr2trunkmf

Related protocols

PCM / TDM

Time-division multiplexed digital trunks such as T1 (24×DS0) and E1 (32 timeslots) framed per G.704 and related recommendations. Framing,…

ISDN PRI

Primary Rate ISDN: T1 23B+D or E1 30B+D with a 64 kb/s D-channel for Q.931/LAPD. Timeslots map B-channels; framing and line coding come f…

ISUP

SS7 call-control user part for trunk setup: IAM, ACM, ANM, REL, RLC and related messages. Circuit identification codes bind signaling to …