The T-BERD 107 Ais a full-featured, hand-held T1 test set designed for outside plant testing. It can be used during circuit installation, acceptance testing, and fault isolation. The T-BERD 107 A can monitor a T1 circuit without interrupting service, generate and receive test patterns during out-of-service circuit testing, and emulate a network device, such as a Network Interface Unit (NIU) or Channel Service Unit (CSU). In addition, the T-BERD 107 A detects and isolates problems related to customer premises equipment (e.g., NIU) and detects problems originating from the T1 span. D1D, D4, ESF, and SLC-96™ framing patterns offer compatibility with a variety of framing formats. An unframed mode is also available for applications where framing is not required. Automated BRIDGTAP™ pattern sequence detects bridge taps on a T1 span by automatically generating 21 test patterns and monitoring the returned signal for errors. Automated MULTIPAT™ pattern sequence generates five standard test patterns with variable dura- tions that eliminate the need to perform separate tests with each pattern. Logic error, bipolar violation, and frame error (CRC error if ESF framing) analysis are performed simultaneously with the associated error rate and eirored seconds measurements. Complete signal analysis includes signal level, timing slips, received clock frequency, and simplex current measurements. In-band and ESF out-of-band loopback codes enable the instrument to loopback or emulate devices that accept eitherin-band or out-of-band loop codes. Bit-Patterned Message (BPM) recognition enables the T-BERD 107A to identify and display BPMs from the ESI' datalink in accordance with ANSI T1.403. In addition, the T-BERD 107A can generate BPMs. Channel drop feature displays user-selected DSO channel signaling bits, data bits, and VF frequency/ level measurements. In addition, the selected DSO channel is dropped to the internal speaker and the VF OUT jack for analysis by an external TIMS test set. SUMMARY category display s either ALL RESULTS OK or any out-of-specification or non-zero results, eliminating the need to search through long lists of test results. AUTO mode lets the T-BERD I07A configure itself to the proper framing, coding, and pattern. No setup is required when monitoring live circuits. Logic error and bipolarviolation (BPV) insertion enables the T-BERD 107 A to simulate span and equipment errors. Line Build-Out selections add troubleshooting capability to uncover marginal problems such as cable crosstalk and bridge taps. Rechargeable battery and AC power adapter provide operating flexibility to meet different testing needs. The lead-acid battery provides four hours of continuous cord-free operation and can be recharged from the T-BERD 107A AC power adapter. VF OUT jack enables the T-BERD 107A to drop a voice frequency signal from one channel to an external test set for analy sis. RS-232 interface connector enables the T-BERD 107A to print test results and test setup for various tests.