User manual

2.1.2 Digital Output – GT864 PY Variant only

 switched voltage is VIN; high side switch

 max. Output 400mA

 short circuit protected

 ESD protected

 under full control of embedded application

The following command has to be used to initialize and to set the digital output:

AT#GPIO=3,1,1 output switched on

AT#GPIO=3,0,1 output switched off

2.2 Mini USB Connector

There exist several different variants of the terminal module, all in (almost) the same housing,

and all equipped with the USB-type connector:

 GT864 QUAD with Audio

The GT864-QUAD Terminal provides "audio signals" on that connector, so you can connect a

handset or microphone/speaker system here (available for the GT864 QUAD only)

 GT864 PY with 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 for the GT864 PY only)

You will find the version of your GT864 terminal (PY or QUAD) at the label on the button of the

device.

By their nature all 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 they are protected against it to a limited extend only, since otherwise the audio

signal would be significantly deteriorated.

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.