Dial-up problems

[JDNSW]

I am later than usual checking in here today. This morning, my ISP's dial-up number (an 019 number) gave a busy signal. They eventually reported that it worked for them, must be my equipment, probably because I was not using Windows. (got a busy signal with a voice phone on either of my two lines). I tried it on my mobile, and got a modem, not a busy signal. I then called Telstra, who seemed a lot more interested than the ISP, for a change, and was told they'd get back within 48 hours. Three hours later, it started working - not sure if this is pure coincidence though.

Anyone know how this setup works? I know the signal from the local exchange to the rest of the network is digital, so I'm guessing that the "modem" I communicate with is actually the exchange, and I suspect the fix may have been to reboot the exchange.

John

[CowsGoMoo]

I'm sure there are people who can explain better than me but I believe the modem will be at the ISP end somewhere (do they outsource this?).

They most likely will have racks of high density boxes containing "bucket loads" of modems to support all their users rather than individual modems per connection.

Although the dial up connection is known as "analogue", the ISPs use special modems at their end to exploit the fact that most of the network is in fact digital.

If you were to connect to "Joe Blogs" by modem, your dial-up signal would go -

Your modem > Analogue (signal to exchange) > Digital (over phone network) > Analogue (to Joe's modem)

When you connect to the ISP, they perform some kind of "trickery" <insert techo description here> at their end and keep the signal digital into their modem equipment.

In a perfect world this results in a 56K connection for data going to you but slower speeds for data coming from you.

If anyone knows more I'd be interested to hear. I'll do some Googling...