NMX920 OEM Integrators Guide
Page 7 of 21
Host Interface Connector
Pin# Pin Name
Type/Direction
1
Description
1-4
PWR
VBAT
Main power supply input
5-8
GND
GND
Ground (Reference ground for all host interface
signals)
9
RXD
TTL/RS232 output
Main serial data receive (optional 5V TTL or
RS-232 DCE compatible output)
10
TXD
TTL/RS232 input
Main serial data transmit (optional 5V TTL or
RS-232 DCE compatible input)
11
DTR
TTL/RS232 input
System power-on control (optional 5V TTL or
RS-232 DCE compatible active edge triggered
input)
12
RFU
No Connect
2
Reserved for Future Use
13
RFU
No Connect
Reserved for Future Use
14
RFU
No Connect
Reserved for Future Use
15
/RADIO_LED
Output
Radio-on indicator (active low 5V TTL output)
16
/RX_LED
Output
Receive packet indicator (active low 5V TTL
output)
17
/MODE_LED
Output
Network mode indicator (active low 5V TTL
output)
18
/TX_LED
Output
Transmit packet indicator (active low 5V TTL
output)
19
/NET_LED
Output
Network contact indicator (active low 5V TTL
output)
20
/PWR_LED
Output
Power-on indicator (active low 5V TTL output)
21
NC
No Connect
22
NC
No Connect
23
SYSON
+5V_IN
System power-on indicator (active high, high
impendence digital output)
24
EXTBAT
-
(Optional) Standby power supply input (4.75-
5.5VDC @ 100mA maximum)
25
NC
No Connect
26
NC
No Connect
27
NC
No Connect
28
NC
No Connect
29
NC
No Connect
30
NC
No Connect
1
Direction with respect to the Modem
2
All No Connects must be left Open Circuit
5.3. RF Port
The NMX920 is designed to operate with a 50 ohm antenna system. It is fitted with
a MMCX miniature RF connector. As an order time option, the RF connector may
be a straight connector mounted on the bottom of the modem for board to board
connection, or a right angle connector on the top of the board pointing out, or
sideways. See Ordering Information for details.
5.4. Power Supply
Careful consideration must be given to the power supply design for the NMX920.
Whilst receive current is in the order of 100 mA, the transmitter requires 1.7 A
