VX2M can be directly interfaced to a host microcontroller which can generally be powered by the regulated
+4.4V output on pin 8 of VX2M. Three I/O pins on the microcontroller port can be assigned to select the first
8 channels on frequency table of the appropriate band for which the module is configured by pulling the P1-
P3 pins low. Channel select pins of VX2M have internal pull-up to 4V supply rail, hence channel selection
operate on inverted logic.
Channel
P3:P2:P1
111
110
101
100
011
010
001
000
433MHz band
433.050
433.075
433.100
433.125
433.150
433.175
433.200
433.225
458MHz band
458.525
458.550
458.575
458.600
458.625
458.650
458.675
458.700
0
1
2
3
4
5
6
7
Digital Received Data Output (RXD) pin is an open collector output, which should be pulled-up to required
voltage swing level (e.g. +4.4V or Vcc).
VX2M has an automatic noise squelching function which is activated when there is not any RF signal at
detectable level on the channel or if the non-coherent noise like interference level is high enough to block
any weak RF signal from being received. SQF is provided as an open-collector output for monitoring which
should be pulled-up to required voltage swing level. SQF output will jump to pull-up voltage level if received
RF signal level at the RF In/Out pin of the module is about 3dB below the level required to produce 12dB
SINAD level on demodulated AF Output signal. SQF pin can be connected to an LED to act as a Carrier
Detect indicator. Pull-up resistor value should be reduced (e.g. 1k) according to the current requirement to
produce satisfactory brightness on the LED used.
VX2M can be configured using any PC/Laptop/PDA having a serial port and modem/terminal program. TXD
(pin 3) of DB9M connector can be directly wired to PGM (pin C10) of the VX2M and SGN (pin 5) of DB9M
connector should be either connected to common ground or pin C9 of the VX2M.
The whole frequency/channel table is user reconfigurable to 128 channels within 5MHz band of supplied
frequency subject to regulatory band limits. Serial Channel Selection via PGM pin gives access to the whole
of regulatory band allocation for 433.05MHz - 434.790MHz (69 channels) or 458.525MHz - 458.925MHz (23
channels).
Radiometrix Ltd
VX2M Data Sheet
page 4
RADIOMETRIX [ RADIOMETRIX LTD ]
