M 2 M C o n t r o l
by Infranet Technologies GmbH
Ph: +49.40.69647-260
Tempowerkring 2
Fax: +49.40.69647-259
21079 Hamburg
Email:
Germany
Web: www.m2mcontrol.de
Technical Manual 1.05, C600 Professional
Page 15 of 24
Headset connector
The C600 unit has a 4-pole 2.5mm jack connector for connecting a Nokia compatible
headset to the built-in GSM modem. The speaker output is amplified through the internal
amplifier and is a differential (balanced) signal. An audio line transformer must be used to
convert the signal to a single ended signal, when connected to external equipment that
does not have a differential (balanced) input. Otherwise the GSM noise will not be
suppressed/cancelled, and will pass through all the way to the loudspeaker. An external
amplifier should be used when connecting a loudspeaker.
The microphone signal is biased internal for active microphones.
4 pin headset connector overview.
Pin
Name
Description
1
Mic +
Microphone positive Input
2
SPK +
Speaker positive output
3
Mic -
Microphone negative input
4
SPK -
Speaker negative output
Please consult the M2M Control IDE online manual for more information about enabling
this feature.
