Reference Manual

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Appendix C: RS232 Pin Assignments - DB9
Pin Assignment Signal Definition
1 CD Carrier Detect Output Used to show an RF connection between radios.
2 TX Transmit Data Output
Used to transmit data bits serially from the radios to the
system device.
3 RX Receive Data Input
Used to receive data bits serially from the system
device connected to the radios.
4 DTR
Data
TerminalReady
Input
Used only in radios in Point-to-Point Slave/Master
switchable mode or for DTR Connect.
5 GND Ground Signal return for all signal lines shared with Pin 9.
6 DSR
Data Set
Ready
Output
Always high when the radio is powered from the 2.5 mm
power connector. Indicated power is on to the radio.
Also, this pin can be used for +12 Volts when powering
the radios directly through the RS232 port.
This is not used on the OEM module.
7 RTS
Request to
Send
Input
The radio does not recognize RTS for flow control. RTS
is used as a control line in RTS/CTS mode.
8 CTS Clear to Send Output
This signal is used to tell the system device connected
to the radio that the radio is ready to receive data.
When asserted, the radio accepts data, when de-
asserted, the radio does not accept data.
This should always be used for data rates above 38.4
KB or there is a risk of lost data if an RF link is not very
robust.
9 GND Ground Signal return for all signal lines shared with Pin 5.
LUM0020CD Rev June-2020 Page 99 of 112 Copyright © 2019FreeWave
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