On Thu, Aug 20, 2009 at 3:09 PM, nyarotho kennedy <kenyarotho@gmail.com> wrote:

@Wash, been off-air for a while. am amazed at the responses, quite
informed. I think Zain are security conscious here coz DTMF is a
signalling format- anyone good with the algorithms used (probably
disgruntled employees of equipment manufacturer) can hack into the
system though its tedious- imagine being in control of Zap/mpesa
transfers! I personally know that DTMF can be decoded using the
Goertzel algorithm or some other advanced algorithm. i dont think
safcom are aware of this vulnerability, but it can be explained coz i
think they(Saf n Zain) have contracts with different equipment
vendors. I have not delved much into DTMF area but the little have
learnt is all out. if that is the Tito i know then you are probably
getting the best response this half of the Sahara!
@muchai, i am in need of your assistance........concerning IMS
Networks, ping me when you are not very busy. thanks n God bless
y'all!

@Nyarotho - Thanks for the response.

I am in touch with some engineers at Zain and they are helping me out. So far I am waiting to have one of my test numbers to undergo a SIM card downgrade from a 128Kb down to a 32Kb SIM card! Not that I know anything to do with those Kb but I will google, just out of curiosity.

I've had a suggestion to the effect that it could be possible "that the SIM-cards you have and your GSM adaptor do not have DTMF features aligned, some GSM Adapters only support up to 32Kb SIM_CARD, our new SIM are 128Kb".

That sound greek to me, but I am willing to give the idea a chance. I've had some very successful tests with my setting, having a safaricom SIM card sitting on the GSM and me calling it both from Zain and safaricom lines.

Now crossing my fingers that Zain gives me a solution. So far, I am in doubt about the 32Kb vs 128Kb SIM cards idea because once that was suggested, I used my SIM card which is an old one with Yes! label (hoping it's one of those 32Kb, or perhaps less:-)) for testing but DTMF still did not work, but I have to give their option a chance still...