Rainbow Electronics GT864-PY - Manual (Page 11)

GT864-QUAD/PY Hardware User Guide
1vv0300756 Rev.0 08/ 05/07
Reproduction forbidden w ithout Telit Communications S.p.A. w ritten authorization - All Rights Reserved page 11 of 23
4 Mini USB type connector
There exist several different variants of the terminal module, all in (almost) the same housing, and all
equipped with the mini USB-type connector:
•
Audio connector: The GT864-QUAD Terminal provides "audio signals" on that connector,
so you can connect a handset or microphone/speaker system here (available only for the GT864-
QUAD)
•
GPIO: The programmable GT864-PY provides digital inputs on that connector, so you can
use external digital signals to control the behaviour of the terminal thereby (available only for the
GT864-PY)
By their nature these 2 different signals are completely different regarding voltage levels, signal
direction and applied energy. Especially the audio signals are quite sensitive to over-voltage, but are
only protected against it to a limited extend, since otherwise the audio signal would be significantly
detoriated. So please make sure you are using the right variant for your application and do not mix up
different variants - especially do not drive any digital signals into the USB-type-connector of the
audio-variant, since that might seriously damage the device.
The USB connector supports the connectivity of a headset or any other audio equipment using the
analogue microphone and loudspeaker interface of GT864-QUAD/PY Terminal. The table below
describes the signals on the USB connector.
Pinning Mini USB connector GT864-QUAD :
PIN Signal
1 MIC -
2 EAR -
3 MIC +
4 EAR +
5 not connected