Modem working not phone

[Jackie24972]

Hi I'm new on here Hello everyone I have a problem with my phone the modem is working but not the phone. Can anyone suggest what could be the problem.
Thanks all much appreciated.
Jackie

 

[SimonH2]

What sort of modem ? If it's xDSL then it could be the filter(s) or it could be a bad connection. A bad connection can block the relatively high DC/very low frequency signal used by the phone while passing what is effectively a radio signal used by the xDSL. If it's VDSL (aka FTTC, Fibre to the cabinet) then it could be a broken connection somewhere between the FTTC cabinet (where the VDSL signal is added) and the exchange.

Standard diagnostic is to unplug ALL internal wiring and test at the master socket with a known good phone (if necessary, check the phone on a friend's phone line). If you have no phone signal, then call your provider (ie whoever has their name on your bills) and report it as a fault.
For "many years" BT have only installed NTE5 master sockets - on these you can remove the screws and the lower half of the front plate. This (if it's done right) will disconnect all the internal wiring and leave you with the master socket showing.

 

[sparkymarka]

The broadband signal will work down one wire of a pair , you telephone won't it needs both ,

 

[ibruceuk]

The broadband signal will work down one wire of a pair , you telephone won't it needs both ,

Any PSTN signal uses a single pair. Phone and broadband are identical as far as the physical layer are concerned; they are both pretty much an AC current on the line in simple terms.

Older phones need the 'ringer wire' which is pin 3 to generate the ringing tone but the actual use of the phone won't be affected other than it not ringing on an incoming call.

Back to the OP - my first thing would be to try out a different handset to see if this is the cause. (I am of course assuming your broadband is some flavour of DSL and not Virgin Media...)

 

[bernardgreen]

they are both pretty much an AC current on the line in simple terms.

The phone also has a DC current when OFF hook which is detected at the exchange to indicate that the phone is OFF hook. The DC is then modulated by phone's microphone. Incoming speech from the other end via the exchange is AC.

 

[ibruceuk]

they are both pretty much an AC current on the line in simple terms.

The phone also has a DC current when OFF hook which is detected at the exchange to indicate that the phone is OFF hook. The DC is then modulated by the speech from the phone. Incoming speech is AC.

Yes I was oversimplifying it somewhat!

 

[cajar]

if you've checked your phone and it's not that, then it probably one leg disconnected somewhere on the line as Simon says, as broadband will keep working over a single conductor.

 

[SimonH2]

... as Simon says, as broadband will keep working over a single conductor.

I wouldn't go that far. But at the high frequencies used, capacitance will allow the signal to bridge a break which blocks the DC needed to make a phone work.

 

[Europlex]

... as Simon says, as broadband will keep working over a single conductor.

I wouldn't go that far. But at the high frequencies used, capacitance will allow the signal to bridge a break which blocks the DC needed to make a phone work.

Seen this happen many times over the years.