The present document applies to equipment designed to operate within the professional mobile radio service and to the
associated frequency planning. It applies to equipment designed for the transmission of data on shared channels.
The present document specifies an access protocol and occupation rules for data communications on radio channels shared
by different users; it also contains two methods of measurement used for the assessment of receiver timing parameters
(characteristics required for the implementation of the protocol).
This access protocol may be used for data communications over channels originally intended for speech use.
This access protocol also permits the sharing of a channel between several independent users of data communications.
More precisely, this access protocol applies to single frequency simplex operation (and two frequency repeater operations
with the repeater in duplex mode and the mobile units in simplex mode). This access protocol is applicable for:
- multiple data only users, independent of each other, which do not share a common central control facility, but may
share a common single or two frequency radio channel;
- multiple mixed analogue speech and data users, independent from each other, which do not share a common central
control facility, but may share a common single, or two frequency, radio channel and where speech is to have
priority over data transmissions.
In the case of analogue transmissions, the corresponding access protocol is known as the "radio-discipline" of the users.
The present document gives freedom for the use of any bit rate, any constant envelope modulation or any type of
communications protocol which fulfils the normative parameters provided by the present document, in order to access a
shared radio channel; within the limits set out in the present document, each group of users may use its own communication
protocol.
This access protocol is (...abbreviated)