Hello Nordin,
On Fri, 03 Jul 2009 14:44:50 +0200, "Nordin" bouchtaoui@gmail.com wrote:
I hope this will at least try to do a LOCATION UPDATE REQUEST. But it suprises me that older mobilephones don't care about SI 1 (and maybe more information on the BCCH) and just try to register whatever in the BCCH is.
I have further investigated the problem. Besides the fact that the channel allocation in SYSTEM INFORMATION 1 is not correct for GSM 1800, this is probably not the reason for the problem.
Most certainly its just one wrong bit, the GPRS indicator in the SYSTEM INFORMATION 3 rest octets.
The current setting is
0x80, 0x00, 0x00, 0x2B
but it should be
0x80, 0x00, 0x08, 0x2B
What might lead to some confusion is the meaning of "L" and "H" in the specification of CSN.1. For the rest octets the bit value is determined by a comparsion (XOR) to the padding byte 0x2B. So the value 0x08 above actually means "L" for the GPRS indicator, which means "No GPRS".
Its seem that some phones are really sensible to this setting, some other GPRS capable phones just don't care and register to the network even if there is no GPRS.
Best regards, Dieter