User manual

5
Repeater Modes
From time to time it is necessary to include a repeater in a system for the following reasons:-
• To extend range
• To circumvent obstacles
• Achieving a radio link where circumstances dicate the use of less efficient antennas
A system using a repeater is inherently more complex than one without and it is recommended that first time
users may wish to discuss the details of system operation with their modem supplier.
Repeater Modes
The RM96xx series modems have three repeater modes, Standard, Repeat All and Automatic Repeat.
These are selected by the normal programming method with the rotary switch in position 3 and using DIL
switches 4, 5, 6 and 7.
Standard Repeater
In the Standard Repeater mode all RM96xx units within the system must be set to the same address. The base
unit is configured as a standard unit, the repeater is set to 'Standard Repeater' and the remote units must be
set to 'Repeater Remote' (see page 14 for switch settings).
The base unit transmits data with a standard header block. To avoid unneccesary interference and the
possibility of the remote units interpreting the base station transmissions, the remote units will not accept
messages with the standard header block.
When the repeater receives data from the base unit, the header block is changed prior to
re-transmission so that the remote units will recognise the transmission.
In the same manner, a remote unit can only transmit data back to the base station via the repeater which
changes the header block to the standard acceptable by the base unit.
Standard Repeater
PC
User
Equipment
User
Equipment
User
Equipment
User
Equipment
Serial
I/O
Serial
I/O
RM96xx
Address 0
RM96xx
Standard Repeater
Address 0
RM96xx
Repeater Remote
Address 0
Serial
I/O
RM96xx
Repeater Remote
Address 0
Serial
I/O
RM96xx
Repeater Remote
Address 0
Serial
I/O
RM96xx
Repeater Remote
Address 0
Notes
An RM96xx in Standard Repeater Mode will receive data from normal RM96xx units
or from Repeater Remote Units providing they are set to the same address.
A normal RM96xx unit will not receive messages directly from a Repeater Remote.
A Repeater Remote unit will not receive messages directly from a normal RM96xx.