jwb@cit5.cit.oz (Jim Breen) (11/15/89)
In article <telecom-v09i0508m01@vector.dallas.tx.us>, desnoyer@apple.com (Peter Desnoyers) writes: > There is no > reason why a telco must treat voice and data calls identically. If you > don't want to risk getting your data ADPCM'd or sent over analog > facilities by some el-cheapo LD company*, you'd better request data > service. In that case, only the guarantees in the spec for data > service hold. > * I don't mean to suggest that any major LD companies would do this. > Someone will, however. Hmmm. Telecom Australia's ISDN service offers two tariff options: "digital telephony" and "Digital Data". The Digital Data is about 5% more expensive. When quizzed on the difference, they advise that at some stage in the future they will possibly introduce either or both of ADPCM or digital speech interpolation unless a customer specifically asks for a pure 64k bitstream. Their unofficial advice is to use the (cheaper) digital telephony option for the time being. I think this is a legitimate Telco option. I also think Telecom here has done the right thing by stating it as an option right at the beginning of the service. BTW, ISDN users need to be aware of some of the implications of international 64k interworking. For telephony there will have to be A-law/Mu-law conversions, which means that fax and data users will need to declare their calls as such at setup time. _______ Jim Breen (jwb@cit5.cit.oz) Department of Robotics & /o\----\\ \O Digital Technology. Chisholm Inst. of Technology /RDT\ /|\ \/| -:O____/ PO Box 197 Caulfield East 3145 O-----O _/_\ /\ /\ (p) 03-573 2552 (fax) 572 1298