Cloud Electronics PM16 - Manual (Page 47)

PM4/8/12/16 & PM4/8-SA Installation and User Guide v1.0 47
Communication between PMs will be via the digital interface, and between the last
PM (effectively the whole network) and the host will be via the analogue interface.
Consideration needs to be given to any zone offsets applied to the various PMs on
the network. For example, in a 12-zone system with three PM4s configured to page
Zones 1 to 4, 5 to 8 and 9 to 12 respectively, analogue port terminals Z1 to Z12
inclusive will need to be wired to the host mixer(s) for correct operation.
Priorities
A potential problem exists in paging systems employing multiple PMs in the form of
announcement or message ‘collisions’. A collision will occur if an announcement or
message broadcast is attempted from one PM while another is already in progress.
As any one microphone will probably be located in earshot of only one zone’s
loudspeakers, it is possible for a user to page or broadcast a message to a zone and
operators at other microphone locations to be unaware of the usage - should they
fail to notice the BUSY LED.
If simultaneous announcements are made, that starting first will take priority and
the later one will be unable to proceed. However, it will often be necessary to assign
a higher priority to one paging station in the system – typically that in a security
office, where it may the source of emergency announcements. In such a case, an
announcement from the high priority microphone will take precedence over any
other announcements already in progress. See “Priority settings” on page 38 for
details of how to assign priorities to each microphone.