Answer:
64 Kbps
Explanation:
ISDN stands for Integrated Services Digital Network. It makes use of two types of channels:
B type : which is used for carrying data/voice
D type : which carries control and signalling information.
ISDN supports two different service levels:
Both BRI and PRI make use of set of B and D type channels for data transfer.
Each B channel or Bearer channel has a throughput of 64 Kbps whereas D channel has a throughput of 16 Kbps.