GPIO on the GXP1200

Contents

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This page describes the input and output of the phone. Related information can be found on the generic GXP page and on the PCB page.

Keyboard/LED connector

Do not pry this band cable loose by inserting a rod or screwdriver in and pulling on it. Rather than gently disconnecting the band cable from its socket on the main PCB of the phone as intended, I ended up pulling it off of the keyboard/LED PCB, which is unrecoverable (well, in a nice way at least).

Let's follow the GXP2020 tradition and number this B1 to B20. The meaning of the connections is as follows:

Pin Meaning Signal
B1 Common ground to LED: MESSAGE /XF
B2 Common ground to LED: LINE1 /GPIO0
B3 Common ground to LED: LINE2 /GPIO1
B4 Ground to red LED: MUTE /GPIO2
B5 Red/green switch? GPIO6
B6 Vcc, LED feedline Vcc
B7 GND, LED feedline GND
B8 Keyboard row, see below D16 in /CE3
B9 Keyboard row, see below D17 in /CE3
B10 Keyboard row, see below D18 in /CE3
B11 Keyboard row, see below D19 in /CE3
B12 Keyboard row, see below D20 in /CE3
B13 Keyboard row, see below D21 in /CE3
B14 N/C, short-circuited to B20 to B20
B15 Keyboard column, see below CLKR0
B16 Keyboard column, see below CLKX0
B17 Keyboard column, see below FSR0
B18 Keyboard column, see below FSX0
B19 Keyboard column, see below DR0
B20 N/C, short-circuited to B14 to B14

Keyboard matrix

The following is the keyboard matrix of the GXP1200.

Matrix B15 B16 B17 B18 B19
B8 1 2 # XFER SW1
B9 4 5 SEND CONF SW2
B10 7 8 SPKR HDSET SW3
B11 LINE1 0 3 LEFT MSG
B12 LINE2 * 6 MENU UP
B13 MUTE HOLD 9 DOWN RIGHT