Company Confidential
9
Raveon Technologies Corp.
3. Electrical Inputs and Outputs
3.1. RS-232/EIA232 Serial I/O Connector
The RS-232 9-pin serial I/O connector is a female 9-pin D-subminiature connector having
the following pins configuration. It is pinned out so that it may be plugged directly into a
computer or PC’s 9-pin COM port.
Front-view of DB-9 connector on modem (female)
Pin
Name
Dir
Function
Level / Specification
1
CD
out
Carrier detect If enabled, indicates presence of carrier.
Logical 0 (+ voltage on RS-232) means
carrier is present. If disabled, it is
asserted (0) whenever the modem is
operational, and not in the configuration
mode. It will be a 1 when the modem is
in the configuration mode. Configured
with the ATR1 setting.
2
RxD
out
Receive data
Data out of the modem.
3
TxD
in
Transmit data Data into the modem.
4
DTR
in
Data terminal
ready
Normally ignored by the
M7
modem.
May control the power-state of the
modem in low-power mode if this
feature is enabled.
5
GND
Ground
connection
Signal and power ground
6
DSR
out
Data Set
Ready
Normally is set to 0 when modem is
powered on and running. Modem sets
to a 1 when in low-power mode or in
command mode.
7
RTS
in
Request to
send
Used to stop/start the flow of data
coming out of the modem TxD pin. 0 =
OK to send, 1 = don’t send. Leave
disconnected if not used.
8
CTS
out
Clear to send
Used to stop the flow of data going into
the RxD pin from the device connected
to the
M7
. 0 = OK to send, 1 = don’t
send. If the
M7
cannot accept more
data, it will negate this signal (set to a
1).
9
Power
In/o
ut
DC power (not
Ring signal)
User may supply the DC power to the
modem on this pin.
