ATEIS DIVA8G2 - Manual (Page 272)

DIVA system 272
© 2012 ATEÏS
5.9.1.3 Vox@net
This document describes Vox@net/MODAN protocol, used for remote control applications.
Written by R. Seassau
The modan protocol is intended to provide communication between two public address and/or voice
alarm systems. One system is declared as master, and the other as slave, and with this protocol, the
master can send announcement request to the slave and also get status/faults information from the
slave. At the beginning, this protocol has been developed for point to point link, but a multi-point
extension has been added (1 master and more than 1 slave ). All the units must handle both modes.
The physical layer is composed of 1 to 4 audio channels (mostly 0dB) from the master to the slave, and
a regular RS232/422/485 serial link between master and slave. In case of multipoint configuration, serial
link can be RS485 (with proper 232/485 interfaces if needed), or any suitable data network.
Serial link default values are 9600 bauds, even parity, 8 bits, 1 stop
Definitions: STX=2, ETX=3, CR=13, ACK=6, DLE=16, NACK=21, SP=32, ENQ=5 with all
values in decimal.
Upper case symbols are fixed.
POINT TO POINT PROTOCOL DEFINITIONS
Commands format: STX command string ETX CS CR where CS is the checksum (exclusive or) of all
characters of command string. For each command, answer can be ACK CR (executed), DLE + CR (not
executed),
NACK CR (not understood). The answers are not inserted inside STX…ETX LRC CR frame.
All commands use logical zones (namely codes) to reduce the size of datas exchanged. For a very
simple implementation on a small system, code 1 can be output 1 and so on. Generally a code is like a
group of zones. Channel refer to 0dB audio signals.
Slave configuration data:
o Channel inputs (4 0dB inputs allocated to channels 1 to 4)
o Channel priorities (4 priority levels allocated to channels 1 to 4)
o Code zones (groups of zones allocated to codes 1 to 99)
Announcement Request: commandstring = Pch code1, code2, code3.
For example P12 means call with channel 1 inside zones grouped on code 2, P21,3 means call
with channel 2 inside zones grouped on codes 1 and 3.
If the command is executed, the answer is ACK CR (all codes were available ) or DLE + CR (at
least one code was not available for this channel).
Announcement Global Clear: command string = C ch 0 0
For example, C100 means clear of announcement running with channel 1. The slave unit must
memorize all the time zones requested for announcement for each channel).
When a clear command is executed, the answer can be ACK CR (all codes were occupied by
the channel) or DLE + CR (at least one code has been taken by another source).
Announcement partial clear: command string = L ch code1 , code2 , code3