User manual
GTR64  http://www.matrix.es/GTR64 
3. ELECTRICAL DESCRIPTION 
All electrical connections to the module are protected in compliance with the standard air and contact 
Electrostatic Discharge (ESD). 
The module uses the following industry standard connectors: 
•  Sub-D 9 pin female (Main RS232 serial port) 
•  High density 15 pin (Secondary RS232 UART and extended I/O interface) 
•  RJ12 6-way (power supply connector) 
•  RJ9 4-way (handset connector) 
•  SIM card reader 
•  FME male coaxial jack (antenna connector) 
3.1 Power Conector 
An RJ11 6-way connector, as shown and described below, serves means of supplying and controlling 
d.c. power to the modem. 
The supply voltage, VCC, required by the modem is in the range 32V d.c. Application of the supply 
voltage does not switch the modem on. To do so an additional active-high control signal, TO_IN, must 
applied for > 0.2s. 
A second active-high control signal, HR_IN, can be used to switch modem off when applied for 1 - 2 
seconds, or can be used to perform hardware reset when applied for > 3.5s. 
TO_IN and HR_IN are referenced to GND (pin 6 on the connector). 
VCC and GND are reverse polarity and overvoltage protected. 
PIN:  Signal  Dir  Limits  Description 
1  VCC  Input  5-32 V DC  Positive power input 
2  VCHARGE  Input     
3  HR_IN  Input  5 – 36 V 
Active high control line used to switch off or 
reset the modem 
VIH > 5V, VIL < 2V 
Power off: 1s < t < 2s 
Hard reset: t > 3.5s 
4  TO_IN  Input 
5 – 36 V 
Active high control line used to switch on the 
modem 
VIH > 5V, VIL < 2V 
Power on: t > 0.2s 
5  3.6V out  Output    3.6V DC reference signal output. Max 75mA 
6  GND  Input   
Negative power (ground) input and return 
path for TO_IN, HR_IN and VCHARGE 
GTR64 Integrators Manual V.1.2  Pag. 13 
Preliminary. Subject to change without prior notice 










