John, at 20:07 on Dec 25 1996, you wrote to Bill Grimsley...

BG> In these days of FO between exchanges, the actual distance between 
BG> subscribers is more or less irrelevant.  Almost ALL signal loss occurs on 
BG> the copper between the subs and their exchanges,

JP> When explained in the above manner, things make more sense. I had no idea 
JP> that the cable between exchanges was in fact fibre optic.

The vast majority of inter-exchange links, both in and between the major
eastern capitals, are already FO, and those that aren't soon will be.

JP> In essence, it's really a matter of the total copper along the link; ie, 
JP> from here to my local exchange, and from the remote modem to its nearest 
JP> exchange.

Basically.  According to Telstra's engineers, the maximum total line loss
between any two subs should not exceed 14dB (actually 7dB for each sub).

JP> I suppose that in summary (and on the assumption that the copper wire in 
JP> said places is clean), the closer both parties are to their local Telstra 
JP> exchanges, the better the connect speeds.

That's it in a nutshell.

JP> Aren't there any OTHER factors which can influence (one way 
JP> or another) the connect rates, or is the equation as simple 
JP> as what I've described above?

Yep, the modems themselves.  For example, the latest US/Canada USR SDL has
apparently just fixed a long-standing bug which had prevented Couriers from
negotiating the 3429 symbol rate (i.e. 33600bps connects) with inbound
calls from most (if not all) Rockwell-based modems.  Needless to say,
Austel Couriers still suffer from this inherent problem, which is probably
why you've never seen an inbound 33k6bps connect from a Rockwell yourself.

Regards, Bill

--- MsgedSQ/2 3.50