If you're just transmitting data then I'd seriously look at buying cheap radio modules meant to do what you're trying to do. That are dozens of places that sell them, and after $20 in parts you'll thank yourself many times over for saving the time and aggravation of trying to fit the wrong part into your project. -Adam Matthew Brush wrote: >Thanks for the info guys ... > >So would it be difficult to interface to the PLL in there? I know nothing >about PLLs except that it probably stands for Programmable Logic something >... but I've read about them not being "extremely" difficult to use. I will >have to do a little more reading obviously. > >My other alternative is to get some of those little RX/TX circuits from: >http://www.rentron.com ... I believe they are called TWS and RWS something >or other. They seem to be popular among roboticians. I wish I hadn't >removed the transceiver circuit from the cordless phone handset, I probably >could have just simulated DTMF on the lines or something to send data back >and forth. Oh well, live and learn > >Thanks again for the help. > >MJ Brush > >----- Original Message ----- >From: "M. Adam Davis" >To: >Sent: Tuesday, May 18, 2004 10:29 AM >Subject: Re: [EE:] Cordless Phone Transceiver Interface > > > > >>I tore apart several phones last year and after many hours of work >>decided that it's better to go with modules that I have data sheets >>for. The only place which sells something like this to hobbyists (that >>I'm aware of) is Laipac. Even then the data sheets don't give you great >>information on how to use them - they tell you how to program the PLL, >>etc but don't give you all the generic values you can use for the pll. >> >>They have some 'easier' transceivers which have microcontrollers to do >>all the heavy lifting - all you have to do is select which of 16 >>channels to use (via 4 pins in binary - can use a dip switch) and >>amplify the audio and microphone. >> >>They are not as cheap as cordless phones ($30 per pair, IIRC) but they >>are not expensive and the time saved is generally worth the money. >> >>If you decide to use the modules in the phone anyway, look at the data >>sheets for the 40 channel transceivers at Laipac. They'll give you an >>idea of what to expect since these modules are usually nothing more than >>a PLL and support circuitry. Then you'll need to either identify the >>chips inside your module or capture the commands going to them so you >>can identify how to set the PLL up and select the channel. >> >>Good luck! >> >>-Adam >> >>Matthew Brush wrote: >> >> >> >>>Hi all, >>> >>>I was wondering if anyone had any information about the little >>> >>> >transceiver modules inside a cordless phone. > > >>>Basically, inside both the handset and the base there is a little >>> >>> >"module" with 15 wires coming out of it. The module looks like a PCB with 2 >shielded boxes soldered on them. I don't wanna rip the shielding off, >because I'd have no idea what's going on in there anyway. On each board >there is also a wire coming off for the antenna. > > >>>I'm assuming that this is a "prefab" module that GE uses in it's 900MHz >>> >>> >cordless phones to avoid re-engineering the RF circuitry for each model. >The board is marked with: Model:26920R (Panasonic). > > >>>I would love to interface my PIC micro controller to this, and my >>> >>> >instinct is telling me that of the 15 lines coming off of the board, there >is most likely Audio In, Audio Out, Digital IO, Digital Clock, Power, >Ground. But how to find out which is which? > > >>>If anybody has any ideas of how I could figure which wires are which on >>> >>> >this board, I would greatly appreciate it. Unfortunately I don't have a >scope. If I contacted G.E. could I get schematics for my phone? Any other >ideas or anyone tried this before? > > >>>I will post my results if I can figure out how to interface to this >>> >>> >module. > > >>>Thanks so much. >>> >>>MJ Brush >>> >>>-- >>>http://www.piclist.com hint: The PICList is archived three different >>>ways. See http://www.piclist.com/#archives for details. >>> >>> >>> >>> >>> >>> >>> >>-- >>http://www.piclist.com hint: The PICList is archived three different >>ways. See http://www.piclist.com/#archives for details. >> >> > >-- >http://www.piclist.com hint: The PICList is archived three different >ways. See http://www.piclist.com/#archives for details. > > > > > -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.