Page 892 of 894 Appendix A: LAPB Data Link Control protocol
553-3001-211 Standard 2.00 September 2004
Asynchronous Balanced Mode
Asynchronous Balanced Mode (ABM) is a balanced, configured operational
mode in which either combined station may send commands at any time and
may initiate certain response frame transmissions without receiving
permission from the other combined station.

Commands and responses

The elements of procedure are described in terms of actions which take place
when a command is received. The classes of procedures are a combination of
the frame structure and the set of elements that satisfy the requirements of a
specific application. The LAPB Balanced Asynchronous Class of Procedure
(BAC, 2, 8) is implemented. This is compatible with both BX.25 and ADCCP
specifications. The basic set of commands and responses is listed in
Table 276 on page 893.
Figure 188
Balanced configuration
Commands
Combined
station Combined
station
Responses 553-3741