DIY mobile phone conference call?

[fitzy]

I have a dozen cheap Nokia mobile phones with active sim cards (used and no longer needed), and i was wonder if its possible to wire up the mic and speaker wires (from handfrees sets) in a way that if 4 or 5 people rang 4 of 5 of the phones, they would be in a chat room, more like a conference. Is this anyway possible? If so, how do i go about wiring it up?
The reason for this is that me and my mates are on unlimited free calls on 02 network, and we could all chat at the same time for free, rather than pay for a conference call or pay thru one contract mobile phone.
If you've any ideas, they would be greatly appreciated,
thank you.

 

[theflyingsquirrel]

The output power for the speaker phone is too low. You cannot just connect a speaker to it. You are going to have some amplifying circuit. Antoher
The easiest way I can think of is to connect the handfree to the cell phone; cut the wire to the headset and mic; solder a 3 pin 3.5 mm jack and a 2 pin 3.5mm jack to the cut wire. Finally, connect a commerical headset with mic or computer speaker and mic to the connectors, or to computer speakers and mic. Then you are done.

You can get some components from here if needed.
http://theflyingsquirrel.ca

Here is a Graphical Resistance Online Calculator and Coversion Table.
http://theflyingsquirrel.ca/ohmcal.php

 

[fitzy]

TFS, thank you for your responce, but i dont think you understand what i mean.
I dont want to amplify the sound so that i can hear thru a speaker.

Just say 4 people want to talk together over a phone call (conference call).
How can i join up 4 mobile phones, so that each of the 4 people can ring each of the 4 phone which i've connected together (ringing in from their own phones). That would be 8 phones in total, 4 phones connected to eachother and 4 phones ringing in to each of the connected phones.
Could it be done?
Can i connect the mic and ear speaker + terminals together and the - terminals together?
Or do in need to add something.
Thanks again for you responce.

 

[theflyingsquirrel]

You mean 4 people (including your friend that has unlimited air time) are in the same room and when you call to your friend, all 4 people can talk together with the unlimited air time phone?

 

[fitzy]

Yes mate.
But i'm only using a chat room as an example.
The 4 people can be anywhere. All they need to do is ring each of the mobile phones that are connected together.
Is it possible to connect 4 phones together using their handsfree kits?

 

[theflyingsquirrel]

Hum,
I think of a way. But I am not sure if it is feasible for you.

I personally are using VOIP for phone.
I ordered a DID number from this VOIP provided.
I can create a ring group from my account and included all your mates in the ring group.
When someone called this DID number, all the phone numbers in the ring group will ring.
The VOIP service provider I am usingn is voip.ms.
You can check it out if you want.
But you are going to need to paid for a monthly fee though.
However, the fee is really cheap.

let me know if that works for you.

 

[fitzy]

Thanks TFS,
i experimented with the handsfree set, by connecting all the + and all the - together. It doesnt work, when i rang the phone, all i got was feed back (squealing).

I have already looked in to conference calling, and 02 does have conference calling, for 8p per minute. 02 gave me a phone number and a code, so anyone can ring the number then use the code, and we can all chat on the same line.
Thanks anyway mate.

I just wanted to be a cheap skate lol.