Ricoh Aficio 2022 customer loses DSL when faxing

[copyaction]

just wondering if anyone heard of this, no problem with copier, fax sends and recieves fine but since they got DSL hooked up they lose the DSL connection for like 2 minutes anytime they use the fax.
Already have filter on the line so it must be an issue with the DSL connection.

[blackcat4866]

Re: Ricoh Aficio 2022 customer loses DSL when faxing

By definition the POTS uses frequencies below 5kHz, and the DSL uses frequencies above 25kHz. So there should be no interference between the two signals.

If the low pass filter was not eliminating the DSL signal from the fax line, the fax would not go through. But the DSL would remain unaffected, since the fax does not (or should not) produce signals in the 25kHz & above range.

Perhaps the high pass filter in the DSL modem is not functioning, making is sensitive to frequencies that it would ordinarily ignore? This seems the most likely, to me.

Just out of curiosity do you have a standalone fax you can temporarily test with? Perhaps your fax is transmitting something in the 25kHz range. The highest G3 transmission frequency I can document is in Canon's proprietary protocol CHT (Canon High-Speed Transmission). Specifically, BCF (Backwards Channel Check: 3280Hz for 600ms +/- 15%). Not even close to 25kHz. If it's truly a problem with the DSL modem, you'll see the same interference with any fax.

Though it shouldn't make a difference, it's cheap and simple to try a different DSL filter. Many surge suppressors have DSL filters built in these days.

Please keep us posted on your results. =^..^=