My understanding is that GSM protocols were largely inspired by ISDN protocols. ISDN had (has) the same short messaging capabilities on its 'D' channel which is the out of band signaling channel (2B+D). Most ISDN phones and Mac/PC softphones had messaging feature built-in.
Slashdot Mirror
My understanding is that GSM protocols were largely inspired by ISDN protocols. ISDN had (has) the same short messaging capabilities on its 'D' channel which is the out of band signaling channel (2B+D). Most ISDN phones and Mac/PC softphones had messaging feature built-in.