X.21
<communications, standard> A digital signaling interface recommended by
ITU-T that includes specifications for DTE/DCE physical interface elements,
alignment of call control characters and error checking, elements of the call
control phase for circuit switched services, data transfer at up to 2 Mbps, and
test loops. 64 kbps is the most commonly used transfer rate.
(2000-02-28)
Nearby terms:
X2 « X.208 « X.209 « X.21 » X.214 » X.215 »
X.216
|