In ISDN, referring to the ability of a device, such as a terminal adapter (TA), to dynamically adjust the number of 64-kbps bearer channels (B channels) to the demands of the call or calls. In one scenario, rate adaption effectively throttles down the transmission rate from 64 kbps to the rate at which the non-ISDN device is capable. Rate adaption also serves to bond multiple B channels into H channels for more bandwidth-intensive applications. Rate adaption is accomplished in North America through the ITU-T V.120 protocol; the European standard is V.110. See also B channel, bonding, H channel, TA, V.110, and V.120.