0-1200bps RS232 radio modem

GDM212 is an 1200bps air rate radio modem with RS232 serial port. The radio unit can operate as a transparent radio link, essentially replacing a wire with classic RS-232 based protocol. It is designed for long rang telemetry, SCADA and remote control application under different weather conditions.
Depending on these radio modems, the range of RS-232 communication can be extended up to 20 miles or more in pure line-of-sight conditions. GDM212 has 12V or 24V operating voltage levels to chose from and low power consumption, it is extremely well suited for outdoor use.


Specifications

1. General 
   (1) Operating frequency range: 400 to 440 MHz 
   (2) Channel spacing: 25 KHz or 12.5KHz
   (3) Number of channels: 60
   (4) ANTENNA IMPEDANCE: 50 Ohm unbalanced
   (5) OPERATING TEMPERATURE: -40 to +70℃
   (6) FREQUENCY STABILITY TCXO:   ±1.5ppm
   (7) OPERATION VOLTAGE RANGE: 12V DC ( 11Vdc to 14.5V  DC)
   (8) STAND-BY CURRENT: 85mA

2. TRANSMITTER 
   (1) RF OUTPUT POWER: 5W to 25W programmable
   (2) OUTPUT 2ND HARMONIC: less than –65dB
   (3) SPURIOUS EMISSIONS:  less than 0.25uW (30MHz to 1GHz)
   (4) MAXIMUM FREQUENCY DEVIATION: ±5KHz
   (5) REFERENCE OSCILLATOR: TCXO
   (6) RF IMPEDANCE: 50 Ohm unbalanced
   (7) CURRENT DRAIN: 6.0A @25W output power
   (8) FM HUM AND NOISE RATIO: greater than –50dB
   (9) AUDIO FREQUENCY DISTORTION: 3% 1KHz for 3KHz deviation 
   (10) AUDIO FREQUENCY RANGE: 300Hz to 3400Hz ±2dB
   (11) TRANSMITTER ATTACK TIME: less than 7ms

2. RECEIVER 
   (1) TYPE OF RECEIVER: Crystal controlled double, super heterodyne
   (2) INTERMEDIATE frequency: 45MHz(1st IF), 455KHz(2nd IF)
   (3) SENSITIVITY: Better than 0.2uV @12dB SINAD
   (4) SQUELCH SENSITIVITY: 0.1uV to 1uV programmable
   (5) ADJACENT CHANNEL SELECTIVITY: greater than –70dB
   (6) SPURIOUS AND IMAGE REJECTION: greater than –65dB
   (7) OUTPUT AUDIO DISTORTION: 3% at 1KHz for ±5KHz deviation
   (8) FM HUM AND NOISE RATIO:  greater than 40dB

3. Data and Interface 
   (1) MODULATION: GMSK
   (2) AIR RATE: 19200 or 9600bps programmable 
   (3) INTERFACE BAUD RATE: 600 - 38400 bps programmable
   (4) INTERFACE DATA BIT: 8 / 7  bit
   (5) INTERFACE PARITY BIT: None / Even / Odd
   (6) INTERFACE STOP BIT: 1 / 2  bit