Ian Greenway said,
> Neil Bothwick has been demonstrating his expertise...
>> I've found the Pace works best when left to its own devices. This init
>> string works very well for me, no line drops and hardly any retrains
>>
>> AT&F+MS=,,,,1%E1S202=32%C3W2\r
>>
> I've got a Pace 56K modem and I tried the above init string but it had
> very little *apparent* effect,
It's more likely to help with a sub-optimal connection. Pace say their
modem is already set up for Internet use and the factory defaults are
all you need. For most people AT&F is fine. The above string helps
some people and harms none.
> When a modem "retrains" to a different speed, I understand the connect
> speed will change, but during retrain, what actually *happens* in
> terms of what a user will see? - Does it pause a download for a few
> seconds? Does it drop the line? etc.
You shouldn't notice the actual retrain, but you will probably see a
slowdown caused by the errors that led to the retrain.
> Will a modem connected at a given speed retrain to a higher speed if
> the line quality improves? If it does, why the concern over
> retraining in the first place?
It should do, but they don't always do what they should. The concern
is partly because some modems connect at a higher speed than they
should and retrain downwards shortly after, giving falsely high
initial connect speeds, the figure most people look at in respect of
their connect quality. This is why I say the connect sped is somewhat
irrelevant. All that really counts is the throughput you get.
Retraining at another time is still an indication of line quality, if
your modem is repeatedly changing transfer speed, you must be getting
a lot of errors and retransmits, which severely harm your throughput.
> Is a retrain something initiated by your own modem, the isp modem, or
> either? (or both?)
It's part of the error correction protocols so it's initiated by the
two modems, they have to find a speed that is mutually acceptable.
> I often play Quake online, which requires heavily sustained comms
> activity. Sometimes the whole thing will just freeze for a few
> seconds. The game server must still be churning out packets since
> other players are still moving around. Is this a retrain? Is there
> anything I can do to improve this?
The most essential addon for online Quake is ISDN, no question. Ping
times in the 30ms range and no error correction overhead make it the
best way to kill peoiple while their modems are still doing all that
klunky A-to-D stuff.
> Today, for the first time, my modem dropped the line. An AT&V1 gave
> the reason as "retrain failure". The line quality number was very high
> - over 100, whereas it is normally about 25. (49333 connect
> almost every time). What causes a retrain failure?
Failure to retrain, i.e. the two modems couldn't agree on a suitable
speed to maintain a good connection. It sounds like your connection
had become very noisy.
Neil
--
Neil Bothwick - http://www.wirenet.co.uk icq://16361788
Connected via Wirenet,The UK's first Amiga-only internet access provider
--
Bill Gates named his company after his penis.
