© Microhard Systems Inc.
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5.0 Network Topologies
‘Network Type’ (S133) is set to 1 for PTP operation.
Note that the Master has a register ‘S141 - Repeaters Y/N’ and the Slave does not. This
register informs the Master of there being one or more Repeaters in this network. The fac-
tory defaults assume ‘no’ and assign a value of 0. If a Repeater is to be installed, and all
the Master and Slave defaults will be maintained, following is a procedure on how to con-
figure a Repeater into this fixed (non-mobile) PTP network:
Master
•
enter into Command Mode
•
change S141 (Repeaters Y/N) to 1 (which means ‘Yes’)
•
save the change using the AT&W command
•
go online with the ATA command
Repeater
•
enter into Command Mode
•
load a third modem with &F7 (PTP Slave factory default settings)
•
change the Operating Mode (S101) from 2 (Slave) to 1 (Repeater)
•
change the Unit Address (UA) (S105) from 2 to 3
•
save the changes using the AT&W command
•
go online with the ATA command
Slave
•
enter into Command Mode
•
change S118 from 1 (the UA of the Master) to 3 (the UA of the Repeater)
•
save the change using the AT&W command
•
go online with the ATA command
This system may be tested by sending text at 9600bps, 8N1 through the RS-232 serial port
of one modem and observing that it appears at the RS-232 serial port of the other modem.
The Slave is synchronized to the Repeater, which in turn is synchronized to the Master. If
the Repeater is taken offline, in a matter of moments the Slave’s RSSI LEDs will indicate
that it is ‘scanning’ for its immediate upstream unit; place the Repeater online and the
Slave will quickly acquire it. If the Master is taken offline, both the Repeater and Slave will
begin to scan.