No Dial tone/ wont connect

Ringing is assigned in system programming, very little chance it was changed by mistake. If Do-Not-Disturb was turned on, that could make a phone stop ringing. If it's just one line on a phone, maybe the system got put in night mode by mistake and night programming isn't identical to day ring. If you have direct access to the phone line check it for dial tone. Often virtual lines are used and you can't check for direct dial tone. On very rare occasion the ringer stops working, which can't be fixed.

Usually on hook telephone line voltage around 40V DC +/- depends on exchange, voltage will drops below 12VDC if its half hook..You will get engage tone/usage tone if voltage drops less than 12V, in this condition you wont get any incoming calls.
You need to open the printer formatter to locate the modem where telephone line inserted..
Let understand why this malfunction happens..
The ring voltage between the line is +120V AC, but it should not exceed more than 200V.. To protect the circuit, line will guarded by component called "VARISTOR". The Varistor will burns if voltage reaches specified or more voltage across it.. Once varistor burns U will get engage tone always... Basic multimeter is enough to check the varistor, put multimeter in diode mode, test both ends of varistor, it should not show zero value or beeping. Some times it may burn, blast or bulge. Remove the faulty component from the circuit with the help of soldering iron, connect the line & verify, if line is good replace with same rating of component.. Chk for the ring & dial tone...
Req tools: Multimeeter, soldering iron, little paste & Led, screw driver set for opening the printer..
Depends on design varistor may fix accordingly which we need to find out the location.. But its always fixed between line in path. pl see the attached sample diagram.
if you are non technical pl don,t try it...Best of luck.. Ex: Varistor Damaged/burnt varistor

If you have another phone connect it to the wall outlet to see if you get a dial tone. This will indicate if your base unit is faulty.
Check the power adapter to the base unit, make sure it is getting mains power.
If the base unit has dual phone lines and if line 1 is only connected and the line 2 has beed selected then you cannot get a dial tone. In the chase press the line 1 to get a dial tone.
If your base unit has only one line then check the phone line at the wall socket make sure it is plugged in tight, also check the the connection at the base unit.
If this does not work then ring the phone company and get the to test your phone line, you may have a faulty line to your home.

Hi did you get this fixed? I am having the same problem.

Hello. If everything else is working, printing and copying, unplug the printer from the power source. Check the telephone line from your phone company by unplugging the fax machine from the wall jack where it is connected to. Plug a telephone device straight to that wall jack and check for a dial tone. If there's no dial tone, contact your phone company. If there is, plug the fax machine back to that wall jack. You can also try replacing the telephone cable with a another known working cable. Plug the printer back to the power source. Check again. Hope this helps.

I would contact your phone provider. It could be a coinceidence that the dial tone stopped working.
DSL does not require dial tone to work.

Headset says ringer off, cannot hear dial tone

Check the cor and cos setting of the phone It shold have the permissions to call outside

Suggest you check battery in non working handset is connected and charged. If this is ok, suggest you check this handset is registered with the base station, as out of the box they arent always set to the same channels