Intercom Ring
This is a service offered by the former Pacific Bell Telephone Company (now part of AT&T) in which you could call other extension phones on your own line.

To activate dial:

*51 (or 1151 on a rotary phone)   For ring pattern "SHORT-SHORT"

*52 (or 1152 on a rotary phone)   For ring pattern "SHORT-SHORT-LONG"

*53 (or 1153 on a rotary phone)   For ring pattern "SHORT-LONG-SHORT"

Hang-up, then wait for another person to answer, then answer yourself when it stops ringing.

Helpful Hints:

1. This service is not available in most areas of the USA. This was a service primarily provided by the former Pacific Bell Telephone Company (now owned by AT&T). Although other telephone companies may have also had the feature as well, in which case you may have this feature available to you. Call your telephone company's business office for more information.