Company Confidential
9
Raveon Technologies Corp.
4. Electrical Inputs and Outputs
4.1.
LEDs
Status LED (TX)
This LED blinks red when the transmitter keys and is putting out RF
power. It blinks green upon the reception of data or RF carrier. It turns orange when
decoding a paging message.
Power LED (PWR)
This LED does a short blink, once every two seconds, indicating to the
user that the power to the modem is ON and the modem is working. When the modem is in
the command mode, this LED will blink on and off, once per second.
4.2.
I/O Pinout
The I/O connector is a 20-pin header, 2mm pin spacing.
Pin #
Function
I/O
Function
1
GND
-
Ground
2
Vcc
I
DC Input
3
Carr Det
O
CD Out. Low for carrier. Logic high for no carrier.
4
TX On
O
Pin is High when module is transmitting. Low when off, receiving, or
sleeping.
5
Data In (TXD)
I
Transmit data input.
6
Data Out (RXD)
O
Receive data output.
7
Enable
I
Low (<.7V) to shut down the module. High (>2.5V) to enable it.
8
Sleep
i
CPU Sleep input
9
CTS
O
Clear to send output. Indicates state of internal buffers.
10
RTS
I
RTS input for serial flow control.
11
RSSI
0
Receiver signal strength indicator
12
3.3V out
O
3.3V out of the M8 module. 50mA max current draw.
13
IOA
I/O
General purpose I/O. 3V digital logic from CPU on M8
14
IOB
I/O
General purpose I/O. 3V digital logic from CPU on M8. By default
functions as DSR. 0= ready&running. 1=sleeping. If enable=0, this
line will =0.
15
Decode Mode
I
3V digital logic with 10k pull-up.
High/open = POCSAG paging receive mode,
Low/ground=data modem mode.
This feature enabled by setting the alternate protocol with the ATMA
command.
16
STAT1
O
Output to drive external dual-color LED. Anode
17
RX Audio
O
Receive and transmit audio output for factory test. Do not connect to
anything.
18
STAT2
O
Output to drive external dual-color LED
19
GND
I System Ground to M8
20
Vbu
Backup battery input to CPU to retain memory. Not required to be
connected to anything.
