Troubleshooting - The telephone only rings once.

The call was blocked. Check to see if the caller is in the telephones Blocked call list.
Voicemail has picked up.
The caller hung up after one ring.
Another answering device in home picked up.
Ring Trip has occurred. Ring trip is caused by an installation issue with your phone line. Confirm that you can make outgoing calls. Then contact your telephone company and inform them that you are able to make outbound calls, but unable to receive incoming calls.