Dial-up on an ADSL enabled line

[AngryTechnician]

After a bit on confirmation of something here...

Our Bursary has a telephone line that doesn't go through the school PBX, but it connected directly to the POTS network. They currently use this with a dial-up modem to connect to our Barclays business banking. We also have access to the newer Internet banking system that works through a browser, but for various reasons that I won't go into, they still need the dial-up.

I want to co-opt the line to install a backup ADSL connection into the school. I know from my own experience that even when ADSL is installed, you can still make a dial-up connection through the voice part of the line (even if it's a bit slower). However, given the perceived importance of the dial-up, I'm loathe to just blunder ahead without being sure.

To that end, I've stuck an ADSL filter on the line already to test the dial-up with the line frequency filtering in place, before ADSL is provisioned. The dial-up has been tested successfully with the filter in place.

My question is this: is this a valid test, or is there something I'm forgetting that could cause problems once the line is actually ADSL enabled?

[SYNACK]

Yes it is a valid test, the filter is just a band pass filter that splits off the inaudable tones from the audable ones (data/voice) on the exchange end there is a filter with the same settings that splits it out again so by using the filter you are already restricting the modem to the avalible voice channel so in theory at least there shoud be no difference when the line is ADSL enabled.

[plexer]

I concur with Synack on his thoughts.

Ben

[AngryTechnician]

Thanks both, I will proceed as planned and blame you completely if it goes horribly wrong.

[tom_newton]

FWIW, we used to have faxes (9600 baud modem inside) running over dsl enabled lines, and still run the franking machine update in a similar way.

The faxes now get their modem chirpings translated to SIP, before being dumped onto ISDN/PSTN depending on how busy we are. Seems to work, oddly enough.