Cell phone calling a landline - landline can barely hear cellphone caller

[Omg]

Shaw installed a new modem last fall at my mom’s and ever since she can barely hear when I call from my cell phone (Telus) and my sister (Fido) calls.  She’s had two techs in and they both said everything looks fine however it clearly isn’t.  From what I’ve been reading on this forum could it possibly be the setup inside the modem?  Maybe the port is not setup?  Thanks for any suggestions as this is driving us all batty 

[rstra]

@Omg does it happen on all cell phone calls only? How are landline calls? 

[Omg]

Yes it happens all cell phone calls.  Landline calls (even from Britain) are fine.  

[rstra]

@Omg  That is very strange, I can’t think of anything that would cause that problem, other than the fact the cell call quality is generally worse than landline.

[Omg]

Thank you for putting some thought into for me.  I’m now wondering if it’s the DSL filter  but I’m just trying to think of every possibility at this point.  Thanks again

[rstra]

@Omg Is it possible to plug the phone directly in to the modem, to bypass the house wiring (and rule it out)?

[Omg]

I’ll have a look next time I’m there.  Thanks for that

[mdk]

@Omg wrote: Landline calls (even from Britain) are fine. 

All incoming calls (land-line or VOIP or mobile-phone) are going through the same Shaw/Rogers box to your handset(s). That suggests what the technicians said, namely that their box is not at fault.

What manufacturer/model of mobile-phones are the callers using? What company is providing their cell-phone services (Bell? Rogers? Telus?).

Any volume-settings on the caller's cell-phone that are not maximized?

What is the voice-quality when your callers use their cell-phone to call your cell-phone (which does not go through the box) ?

[Omg]

The cell phones are Bell Fido and Telus.  The landline starts out with her hearing us fine however she can’t hear as the conversation goes on.  Sometimes it’s fine for a few minutes and other times she can’t  hear us right away. 

[mdk]

@Omg -- Bell does not own Fido -- Rogers does. Telus owns Koodo.

It is possible that the "fading-out" is a problem with her equipment not hearing you as your call proceeds.

Is it possible that she is accidentally turning-down the speaker-volume ?

If you hang up, and re-dial her, is the quality any better?