This Standard ECMA-28 is an optional extension of Standard ECMA-16 on Basic Mode Control Procedure for Data Communication Systems.
This means that:
- those systems which conform to Standard ECMA-16 do not necessarily have to include the functions described in the present Standard.
- systems implementing the functions described hereafter must comply with the present Standard to conform to the Standard ECMA-16 on Basic Mode Control Procedures.
This Standard defines the Multiple Station Selection as an extension to the Basic Mode Control Procedures for Data Communication Systems.
When a system is designed to work both with and without the Multiple Selection Procedure, some means must be provided for the Master Station to notify the Slave stations which procedure is to be entered (for example, by assigning two different addresses to each station having both facilities).