14
Length of RS-232 cable should not exceed 15 m.
ATTENTION!
Length of power cables < 10 m
Length of signal cables < 30 m
For longer cables it is recommended to use external overvoltage protection.
5.5. Power supply
Power cables should be connected to terminals '1' and '2' with an appropriate polarity.
Pin Descri
ption
1
+V - Positive pole of power supply
2
GND - Negative pole of power supply
Connection diagram:
ATTENTION!!!
Improper power supply may result in faulty operation and damage
the module!
6. Starting the module
Starting
MT-301/302/303/304
module requires few basic activities.
Recommended sequence:
1. GSM antenna attachment.
ATTENTION!!!
The antenna has to be attached at every power up since it is a
necessary transmitter load.
The module exchanges information with available GSM networks in
order to test availability of performing emergency calls (112) even
without SIM card