Connecting Old phone speaker and mic to circuit board

[jarwulf]

Hi, I'm in the process of trying to figure out how to connect old phone components to a modern gsm shield. And hopefully not fry anything. These are the:

mic and speakers
bell
dial
hookswitch



First I want to start with the speakers and mic. Here is the old phone. The wires look like they are spade style connectors. white and green are for the speakers, red and black are for the mic.





Here is the gsm shield in question. It has only one obvious 'audio' barrel connector that looks like its designed for those audio jacks you find on earphones. Its two in one for both speakers and mic.





My question is how would you 'interface' the old phone connectors with the gsm shield? I don't want to zap my fancy components so I want to be careful.




Here is the schematic for the gsm shield. I can post the schematic for the old phone itself if anyone needs it.


Here is the wiki page for the gsm shield. It claims to take a 5V-12V power supply

http://wiki.epalsite.com/index.php?title=SIM900_Quad-Band_GPRS_shield_with_Micro_SD_card_slot#Purchasing_this_module


Oh and if you have any suggestions about connecting the other components I'd like to hear them too. I think maybe they can be simply attached to individual pins but I haven't worked all the details out.

Thanks

[Phonesrfun]

What, pray tell, is a gsm shield, and what kind of mic input is it set up to take?

[Phonesrfun]

Dave Hunter (DavePEI) might have experience with having old phone components work with modern electronic devices.  Phones use carbon mic's.  Perhaps the device you have needs either an electret or a dynamic mic of some sort.

[G-Man]

What, pray tell, is a gsm shield, and what kind of mic input is it set up to take?

I suspect there is a language barrier since the seller is Epalsite and is based in ShenZhen, China.

[G-Man]

Other than tx/rx elements, it is doubtful that this board is capable of interfacing with analogue components such as a ringer or conventional dial. It would be unable to originate calls nor ring on incoming calls without a proper interface and data instructions.

[twocvbloke]

Looking at the pictures, that device looks like it's meant to interface with an Arduino, a device used as a basis for many a custom electronic device, I'm sure it could be interfaced with a real phone with all the associated hardware, but I haven't a clue how...

Might be worth looking on an Arduino forum where they'd be better suited to answering this question...

[Kenton K]

I actually have a cell phone telephone myself! On mines, there is another board that is acts like the controller. That programs the GSM module.

The phone works like a rotary dial phone, just portable!

Ken

[jarwulf]

What, pray tell, is a gsm shield, and what kind of mic input is it set up to take?

A daughter board that plugs into a microcontroller board to give it more functionality. In this instance a connection to the gsm mobile phone network.

Other than tx/rx elements, it is doubtful that this board is capable of interfacing with analogue components such as a ringer or conventional dial. It would be unable to originate calls nor ring on incoming calls without a proper interface and data instructions.

analog phones have been connected with different boards from the one I'm using so it might be plausible. The audio jack looks like it takes earphones. Not much in the way of fancy electronics between there right? Just wires or something? Just wondering what I could do to connect the spade connectors to that thing and have the info get through.

Looking at the pictures, that device looks like it's meant to interface with an Arduino, a device used as a basis for many a custom electronic device, I'm sure it could be interfaced with a real phone with all the associated hardware, but I haven't a clue how...

Might be worth looking on an Arduino forum where they'd be better suited to answering this question...

Yeah, they haven't answered yet though...

[G-Man]

As I have already mentioned connecting the tx/rx elements is the easiest, however the other components remain a challenge to interface with the (lone) board you have shown us. Part of the problem is the seller improperly refers to the audio interface jack as an "earphone jack" even though it is used to connect both tx and rx elements to the board. First, you need to determine the board's native input and output impedances and levels to make sure the elements in your handset are compatible. If not it would be very simple to replace them with those that are suitably matched.

Before you embark on your project you should familiarize yourself with the basics of wireline telephony. This would include the basic parameters for rotary dialing, ringing voltages, etc.


Yes, we know that it is associated with an Arduino, that much is very obvious, but what about an interface for the rotary dial and a source of ringing generator for the bell that you want to also connect?  There are others who have successfully used on-board GSM transceivers to create the ultimate cordless telephone using traditional vintage instruments.

Since you stated that someone else has used this specific board to create one of these novelties you should contact them for complete construction details. Otherwise it would appear that it may be too much of a challenge for you since you appear to have difficulty in comprehending how to interface the tx/rx elements which would be the simplest of the task for implementing your project.

Here are a few links showing the interfacing of GSM and Arduino that may be of interest.

•   https://www.sparkfun.com/products/retired/286
•   http://www.youtube.com/watch?v=iQwSiOol_Ug
•   http://www.instructables.com/id/Interface-a-rotary-phone-dial-to-an-Arduino/
•   http://forum.arduino.cc/index.php?topic=69934.0
•   http://www.geekosystem.com/wireless-candlestick-phone/

[Kenton K]

I bought a kit from this guy. Works great!

http://www.rotocell.blogspot.com/

[Nick in Manitou]

I admit that I had to look up GSM and Arduino because I had no idea what was being discussed, but the kit that the link connects to looks pretty brilliant to me!

I don't see a need myself as I still have a land line...but perhaps in the future??

[twocvbloke]

I've thought about making my MOD Mk.28 a GSM-enabled phone, seeing as it has a clamp on the handset to hold it in place (possibly cos it was meant for the Royal Navy) making it the perfect portable phone...

[Phonesrfun]

Should this be moved to off topic?

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EDIT:  So moved . . .