GSM Data Call (CSD)

[heuven]

Hi,

I have an application which uses a CSD data call (RCall). We can send data from one GSM phone to another GSM phone using only the phone number. This works for KPN Mobile SIMs (Netherlands). It does not work for my VodaFone and T-Mobile SIMs currently. I talked with VodaFone support and they commented they have to activate an additional data number on the SIM card.

Now some questions:
* Using RPhone you can enumarete the lines of the phone, say N95. This gives: Line1, Line2, Data and Fax. Is the number of lines determined by the phone? Or is it the SIM card which determines the number of lines?
* Does someone know a good website which explains about the phone numbers which can be associated with a SIM card? E.g. it seems for VodaFone NL the data number for the SIM card does not necessary match the voice number associated with the SIM card. For my KPN SIMs it does.

Seeing forward to some comments. Thanks!

Best regards,

Rene Heuven

[heuven]

Hi,

So as far as I understand the SIM card does not contain any phone numbers. The SIM card has an IMSI number which uniquely identifies the SIM card. The IMSI number is used as the primary key to find a HLR record (Home Location Register is a GSM network component). The operator stores the associated primary phone number (voice) of the SIM in the HLR record. SIMs can also have secondary phone number (for data and fax). This is what most operator use.

If the operator employs a GSM Single Numbering Scheme within the HLR, then the voice and data number are the same.

a) Is this correct?
b) Is there an overview in the internet which operator employ a GSM Single Numbering Scheme?
c) Do T-Mobile and VodaFone not have a GSM Single Numbering Scheme? Does this only apply to the Netherlands or is this the case worldwide?

BR,

Rene