How do I fix a phone that does not work when the modem says Check telephone line?
Answer
A Check telephone line message usually means the cord, wall jack, or modem phone port connection is loose or dead. Reseating the phone cord, restarting the modem, and testing a basic corded phone on the PHONE or TEL port often isolates the problem.
Before you start: stop right away if…
- Do not share provider account passwords or one-time codes with anyone who calls unexpectedly about the phone line.
- Unplug modem power only; avoid forcing connectors or opening the modem case.
Follow these steps
Reseat the phone cord
Unplug the phone cord from both ends and plug it back in firmly at the telephone and at the modem or wall jack.
You should see: The connectors click in securely and the Check telephone line status may clear or stay for further testing.
Restart the modem
Unplug the modem power for 30 seconds, plug it back in, and wait 3 to 5 minutes for it to fully restart before testing the phone again.
You should see: The modem finishes booting and the phone line status updates.
Test with a basic corded phone
Plug a basic corded phone, if you have one, directly into the modem’s PHONE 1 or TEL 1 port using a different phone cord.
You should see: You either get a dial tone on the test phone, or still no dial tone, which helps separate a handset problem from a line or modem problem.
Check for modem phone-line indicators
Look at the modem lights or status page for phone-line, VoIP, or service indicators after the restart, and note any warning that remains.
You should see: You can tell whether the modem still reports a telephone-line fault after the cord and power checks.
Contact the internet or phone provider if the line stays down
If a known-good corded phone still has no dial tone on PHONE 1 or TEL 1 after the restart, contact your provider with the Check telephone line message and the tests you already tried.
You should see: Provider support can check the voice service on the account or schedule a line repair.
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Extra tips
What to look for: A Check telephone line or check phone lines status on the modem, plus no dial tone or failed calls on the connected telephone.
Before you change anything: Note which modem port the phone uses, such as PHONE 1 or TEL 1. Have a basic corded phone and spare cord available if possible. Avoid unplugging internet coax or fiber cables you do not need to touch. Never share account passwords with unexpected callers claiming to fix the phone line.