NEC P3 Pinout & How to Build a Modem Adapter 

(Written in crappy english by SkioS, 1995)



Well if you've got a NEC-P3 and want to use it with your modem I hope this

file helps you make the wirings... you'll need some electronic skills...

First you  have to buy one of these lighter adapters in order to get a

connector for the phone, most of them will come with all the pins and are

quite easy to open (usually just two screws). If you're lucky pins will be

already numbered on the adapter, if not use the following pinout:

  _____________________

 /                    /|

|--------------------| |   As seen when you get the cable (NOT the phone !!)

| 6            1  _  | |   and look at it from outside (before opening it)

|                (_) | |

| 12           7     | |

|--------------------|/



Pins are as follows:   1 - Audio out (EAR)

                       2 - Audio out (EAR/SPEAKER)

                       3 - Audio out (SPEAKER)

                       4 - SDATA (Serial Data)

                       5 - No Connect

                       6 - VCC (+8v)

                       7 - No Connect

                       8 - Audio in (MIC)

                       9 - GND

                      10 - BUSY

                      11 - SCLK (Serial Clock)

                      12 - GND



As you see Audio is sent out on several pins. The most usual is to get it

from pin 2, but I *guess* you can get it also from pin 1 for modem usage.

Also you'll have to make 2 pullups on pins 2 & 3 to let the phone know it's

attached to an external device and stop using its own ear, mic & speaker. Do

it as follows:



   3-----/\/\/\----- Vcc            2-----/\/\/\----- Vcc

          1 k                         |    47 k

                                      |

                                      |-----> Audio Out



Well, once you know how to get audio in & out from the phone just get that

file from DaveX on how to build a modem andapter for the Motorola phones

and build it just the same. You should use capacitors in order to provide

DC isolation. It's also a good idea to power the phone from the adapter,

that way you won't run out of batteries :))



If you've got any doubts or comments just leave me a note (SkioS) on some

board like Arrested Development, Hackers Haven or DAC-UK... Have fun !!!