Abstract: The performance of digital subscriber loops is tested through transmission, reception and analysis of a multi-tone power ratio (MTPR) waveform, containing plural discrete tones having equal spectral spacings and notches periodically distributed among the tones. The noise floor at a missing sub-carrier spectral location is integrated and compared to signal power of an adjacent sub-carrier within the test vector waveform. From these two values, MTPR is determined for various carrier locations, so that maximum theoretical loop payload can be calculated. To generated a figure of merit (FOM) under test, a data modem is placed at each end of the loop. The FOM obtained from MTPR analysis is channel based, not equipment based, and is independent of receiver implementation. Before placing a new customer in service, the MTPR FOMs for a number of loops are compared to bit rate information in a database, which correlates MTPR with a bit rate for a specific modem.

Abstract: A wireless butt set for testing a telephone line includes a base station that is connectable to tip and ring leads of a line under test and is configured to be operated by a wireless telephone handset. The handset is detachably nestable with the base station to form a hand-held integrated butt set assembly. This configuration allows a craftsperson to directly or remotely control the test set using controls of the wireless telephone handset. The internal circuitry of the base station is placed in a high impedance line-monitoring mode without going off-hook, in response to one ‘click’ of a talk switch of the handset, and goes off-hook in response to a ‘double-click’ of the talk switch the handset.

Abstract: The performance of digital subscriber loops is tested through transmission, reception and analysis of a multi-tone power ratio (MTPR) waveform, containing plural discrete tones having equal spectral spacings and notches periodically distributed among the tones. The noise floor at a missing sub-carrier spectral location is integrated and compared to signal power of an adjacent sub-carrier within the test vector waveform. From these two values, MTPR is determined for various carrier locations, so that maximum theoretical loop payload can be calculated. To generated a figure of merit (FOM) under test, a data modem is placed at each end of the loop. The FOM obtained from MTPR analysis is channel based, not equipment based, and is independent of receiver implementation. Before placing a new customer in service, the MTPR FOMs for a number of loops are compared to bit rate information in a database, which correlates MTPR with a bit rate for a specific modem.