This Standard ECMA-27 is an optional extension of Standard ECMA-16 on Basic Mode Control Procedure for Data Communication Systems.
This means that:
i) those systems which conform to Standard ECMA-16 do not necessarily have to include the functions described in the present Standard,
ii) systems implementing the functions described hereafter must comply with the present Standard to conform to Standard ECMA-16 on Basic Mode Control Procedures.
The procedures described in this document fall into two categories, namely ABORT and INTERRUPT.
ABORT procedures are always initiated by the Master station wishing
- either to stop transmitting a block of information before its normal end (ETB or ETX) but without returning to control mode or neutral,
- or to stop transmitting at any time during the information transfer phase and then return to control or neutral status.
INTERRUPT procedures are always initiated by the Slave station which desires to stop receiving either instantaneously or within a short period of time.