[comp.dcom.telecom] CCITT from NZ

Glenn_A_Story@cup.portal.COM (06/05/88)

>>From: paul@csnz.nz (Paul Gillingwater)

>> In NZ the local PTT (Telecom NZ) REQUIRE any Bell/CCITT standard
>> modems to have their Bell modes disabled (firmware change) before
>> they will allow them to be connected to the network.  I understand
>> this is ostensibly because some of the Bell tones used are similar
>> to exchange control frequencies, and crosstalk could interfere
>> with other users of the exchange (e.g. by disconnecting them).

>> The implications of this are that any LEGAL modem in NZ _cannot_
>> dial direct to the US for data access, but must go via NZ Telecom
>> Pacnet gateway for protocol/standard conversion (hints of 
>> forestalling competitive networks?? :-), and this will only work
>> for datasources that are actually connected to a recognised
>> network with existing gateway.

The manual I got with my Hayes modem said that Bell 212 mode (1200 bps) and
the CCITT mode for 1200 bps were very similar, and often work interchangably
(They didn't say what the difference is--does anyone out there know??)

This means you should be able to connect via direct dial to most U.S. modems
at 1200 bps.

Moreover, at 2400 bps, CCITT is the only widely used standard--it's what my
Smartmodem 2400 uses, for example).  Thus at 2400, you should have no
problems on this account.

As an aside, I used to make direct-dial calls from Tokyo to my company's
headquarters in California.  About 30-40% of the calls got as far as
"carrier detect", and were thereafter successful.  The remaining calls showed
carrier detect momentarily and then disconnected.  I never knew why, although
I theorized that it had to do with whether I got a cable or satellite circuit,
but I didn't know which one worked.)

Regards,
Glenn