GSM Shop GSM Shop

Welcome to the GSM-Forum forums.

You are currently viewing our boards as a guest which gives you limited access to view most discussions and access our other features.
Only registered members may post questions, contact other members or search our database of over 8 million posts.

Registration is fast, simple and absolutely free so please - Click to REGISTER!

If you have any problems with the registration process or your account login, please contact contact us .

Go Back   GSM-Forum > GSM & CDMA Phones / Tablets Software & Hardware Area > Nokia > Nokia Hardware & Hardware Repair

Nokia Hardware & Hardware Repair all what you need for Hardware Repairing for Nokia Phones. Before writing any thread here try to check the Frequently Asked Questions Section.

LinkBack Thread Tools Display Modes
Old 11-07-2003, 00:41   #1 (permalink)
Junior Member
Join Date: May 2003
Location: Ashgard
Age: 40
Posts: 12
Member: 29497
Status: Offline
Thanks Meter: 2
Nokia voice encryption device project

Hi there guys ! Yesterday, I had a project ideea. I thought about a gsm encryption device. The

A5 algorythm is safe enough for a lame hacker who want to tap a conversation over the air, but

the guys from the phone company can listern to you quite easy. So , why not building a few

crypting devices, and double encoding the communications between a few phones ...
I thought about two methods of doing this.
1. The encoding device can be inside the phone, inserted between the A/D D/A converter and

the main processor, where the digital signal is A5 encrypted.I studied Nokia 3310 schematic,

and found out quite interesting things.
COBBA asIC provides an interface between the baseband and the RF circuitry . COBBA performs

A/D conversion of the analog signal comming from the microphone, and fr the transmit path

COBBA performs D/A conversion.COBBA is connected with the main processor MAD2WD1 with two

serial interfaces, one for transferring rx/tx signals between MAD2WD1 and COBBA, and one for

transferringcodec Rx/Tx samples.I thought about cutting the PCM samples lines ( rx and Tx )

and inserting a microcontroller programmed to crypt theese samples. As you can see in the

pictures, on theese lines there are four fumpers ... so I think that can access these lines,

somewhere on the surface of PCB, without desoldering MAD2 or COBBA. If someone knows where

theese jumpers are located on the PCB please feel free to mail me.

2.The encoding device can be done outside the phone, conected at Rx/Tx on the external

accessory connector, and the call will be in fact a data type call. But this in far more

complicated.I have an ideea doing this, but I would prefer the first way.

If someone is interested in this project and can help somehow, please feel free topost here .
Thank you
Attached Images
File Type: jpg cobba.jpg (19.3 KB, 143 views)
  Reply With Quote
Old 11-07-2003, 00:41   #2 (permalink)
Junior Member
Join Date: May 2003
Location: Ashgard
Age: 40
Posts: 12
Member: 29497
Status: Offline
Thanks Meter: 2
... and MAD_2

Attached Images
File Type: jpg mad2.jpg (64.8 KB, 130 views)
  Reply With Quote
Old 11-09-2003, 13:43   #3 (permalink)
No Life Poster
Join Date: Nov 2002
Location: slovenia
Age: 44
Posts: 589
Member: 18028
Status: Offline
Thanks Meter: 19
thats wery nice but i dont think for you to make this try to find this lines on defect pcb and cut them than put tini wire to botom conector for headphones cut this lines to to prevent shortcircuit than you can use your project.
but the best way is that you use your project outside the phone with headphones and ext mic(just conect mic and speaker to project and other phone also so you dont need to cut any wire)
  Reply With Quote
Old 11-09-2003, 14:16   #4 (permalink)
Junior Member
Join Date: May 2003
Location: Ashgard
Age: 40
Posts: 12
Member: 29497
Status: Offline
Thanks Meter: 2
I don't think so ...

I don't want to make an analog encryption. I want I have to code a digital signal. Let's say that I convert an analogue signal from external mic to digital, I Xor the signal with some noise , and then I convert it back to analogue to send it via mic. phone input. It won't be good, because of the mic line bandwidith.
I don't like either the internal device sollution, I want some external device, but... it seems that I don't have a choice.Any other ideeas ?
  Reply With Quote
The Following User Says Thank You to MegaADY For This Useful Post:


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

Similar Threads
thread Thread Starter Forum Replies Last Post
Using old Nokia LCD in your projects Dave.W GSM Programming & Reverse Engineering 3 02-17-2009 19:42
Nokia voice encryption device project MegaADY GSM Programming & Reverse Engineering 5 11-18-2003 22:08
voice encryption device project MegaADY Hardware Repair by brands 3 11-07-2003 21:00


All times are GMT +1. The time now is 14:24.

Powered by Searchlight © 2020 Axivo Inc.
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
- GSM Hosting Ltd. - 1999-2017 -
Page generated in 0.79400 seconds with 9 queries