Abstract: An improved trunk identification system for identifying an inbound trunk line selected by a telephone company routing system upon completion of a test routine by associated test equipment. The improved trunk identification system provides for multiplexed use of dual-tone multi-frequency receivers and decoders so as to ensure reliable and economical detection of a specified DTMF tone used to signal the completion of a test routine.

Abstract: A telephone line analyzer provides automatic attenuation measurement of tie trunk lines and other telephone lines through measurement of the electrical level of a tone responder. The analyzer is primarily directed to testing telephone lines interconnected between trunk line selectable computerized private branch exchanges (PBXs) of the same user. The analyzer automatically dials a remote PBX through a desired tie trunk line; activates a remote tone responder; and measures and records the test results. The analyzer may also perform echo return loss measurements.The analyzer is user programmable and it can be set to initiate line tests at predetermined times so as to minimize interference with the normal telephone line activities of the user.