In a single 4 lb (1.8 kg) package, the 635 includes all the basic T1 testing capabilities you would expect in a larger and more expensive tester. It performs bit-error tests, detects framing type, line coding and bit pattern, and displays signal level, frequency, clock slips, errors and alarms. The 635 transmits the most commonly used loop codes, including HDSL. Full, unframed and fractional (56k and 64k) T1 are supported, along with display of signaling and data bits and capture of DTMF digits. Plus, individual voice channels may be monitored on the built-in speaker or over a headset. Eleven standard BERT patterns are available, including a 64-bit user-defined pattern. The 635 also includes a "through" mode where the incoming pattern is retransmitted. Errors - including bipolar violations, logic and frame bit - can be injected to confirm proper handling by the network. Two receivers permit detection of any clock slips. Multiple receiver input types allow terminated, bridged or monitor (DSX) connections. Either recovered or internal clock references can be selected. AMI or B8ZS line coding can be transmitted and received, and SF, ESF, SLC96 and unframed framing are supported. The 635 is compact, rugged and easy to use. Just plug it in and you can immediately see essential information without scrolling through layers of menus. The 635 automatically detects framing and line coding type and instantly displays any errors or alarms. A history indicator helps track intermittent problems. Includes 635 QuickBERT-T1, CO Adapter, HDSL Field Adapter, T1 Repeater Access Adapter, user guides, cables and adapters