Basic rate ISDN interface consists of two voice channels of 64KBPS each (Called B Channels) and one data channel of 16KBPS (Called D Channel). With C Channel (for Link Co-ordination) of 16KBPS the aggregate data rate becomes 160KBPS. This is demonstrated with the above 2 terminals supplied.
Two telephone lines from PABX (or from Two Telephone land lines) are connected to ISDN terminal with exchange interface called COT terminal. The voice signal from the lines are converted to PCM signals of 64KBPS. This occupies the B Channels (B1, B2) the line signaling (like off hook, ringing) are converted to data signals are formatted as per ISDN Protocols.
ie., 2B+D and the aggregate 160KBPS signal is line coded to 2B1Q format before connected to the copper pair. The ISDN terminals called RT Terminal with subscriber interface is also simulate to the above.
These two terminals when they are interconnected through ISDN signals, with EPABX connected to COT and telephones connected to RT acts as an ISDN link with two telephones on a single pair of wire.
Specification :
No. of Voice Channels : 2
Voice Coding : PCM
B Channel Data Rate : 64KBPS
No. of B Channels : 2
D Channel rate : 16KBPS
Signalling : D Channel
Aggregate ISDN Data rate : 160 KBPS
Line Coding : 2B1Q
No. of Voice Channels : 2
