User manual

AGM Spread Spectrum Radio Manual
14
SSR’s as Repeaters
SSR’s as Repeaters
Store and Forward
The modules can be configured as simple “store and forward” repeaters by attaching a
hardware loopback (“repeater”) adapter that loops received data back into the module for
retransmission. This mode allows the radio to store and forward up to 430 bytes.
Usage Guidelines
• Three wire RS232 must be enabled. Jumper pins 3 and 5 on screw terminal.
• Two loopback repeaters cannot be within transmission range of each other as
they will continually repeat data back and forth to each other.
• The module initiating the communication will receive an echo of its own
transmitted packet.
• The repeater will buffer incoming received data and retransmit it when there is a
break in receiving of more data.
• In the absence of a loopback adapter, use a shorting strip to create a short
between TXD and RXD, pins 2 & 3, of the DB9 female RS232 connector.
Streaming
Because of the great price value of the modules, it is cost effective to configure two
modules (‘module 1’ & ‘module 2’) to act as a streaming repeater between a source and
a destination module. To configure this repeater, assign the two modules each to a
different channel (ATHP) and connect the serial ports using a null-modem connection.
Module 1 should share a channel with the source module and module 2 should share a
different channel with the destination module. The source module will transmit data to
module 1 which passes through the null-modem connection to module 2 which forwards
the data to the destination.
This configuration allows for less delay in the transmission as the repeater node can both
receive and transmit at the same time. It allows for several repeaters in a row in order to
reach a destination.
Usage Guidelines
• Two antennas must be used. Antennas must be a minimum of 8 inches apart.
Additional antenna separation and use of directional antennas will reduce the
possibility of interference between the two modules.
• Three wire RS232 must be enabled. Jumper pins 3 and 5 on screw terminal.