D900/D1800 GSM, ( (PPS)/ ) IN/CAMEL. GSM , , GSM, . GSM PPSC ( ) SCP ( ).
SCP/CSE GSM , , , , , (CFU, CFNR). . SCP/CSE IN/CAMEL. GSM , .
SCP/CSE ( GSM ) , (, ""). GSM (USSD DTMF) SCP/CSE. AOCI GSM , .
SCP/CSE, , SCP/CSE " D900/D1800" ( IN/CAMEL ICM "Siemens" . " IN").
GSM . MCR , , MSC (-SSP) GSM . ( MCR) MTC, MSC ( -SSP) ( 3.1.16 " ").