CIDCW primary/secondary arbitration

A system is disclosed allowing a plurality of conforming customer premise equipment ("CCPEs") on a single telephone line to display a third party's caller information while users are communicating with a second party. Through a self-arbitration process, one CCPE of the plurality of CCPEs is a primary CCPE, whereas the remaining CCPE(s) are secondary CCPE(s). While the users are communicating with the second party using any one or more of the CCPEs, each CCPE detects whether a CPE alerting signal ("CAS") tone has been transmitted by the central office, thereby detecting when the third party is calling. Each CCPE responds by disconnecting the CCPE's telephone from the telephone line. After all of the CCPEs are on-hook, the primary CCPE then goes off-hook and transmits a CAS acknowledgement ("CAS ACK") signal to the central office. All of the CCPEs then wait for the central office to transmit the CID information in response to the CAS ACK signal. To implement the self-arbitration process, each CCPE includes a signal detector to detect a signal having a frequency out of the voice band. If the CCPE detects this signal, then the CCPE enters the secondary mode. However, if the CCPE does not detect this signal, then the CCPE enters the primary mode.