The T-BERD 307 is a handheld test instrument specifically designed to fully test DS3 circuits. The DS1 Analysis Option (Option 307-1) adds full DS1 testing capability. A T-BERD 307 with the DS1 Analysis Option installed can perform the following functions: • Identify timing problems by accessing the DS1 timing reference from either DS3 or DS1 access points. • Test far-end equipment by transmitting appropriate loop codes to loop back a transmitted signal, then verifying the transmitted data is received without errors. • Troubleshoot individual DS1 Channels within a DS3 signal by inserting test patterns or loop codes on one or all DS1 channels. DS1 channels can be dropped from the received DS3 signal to test and monitor. • Measure VF level and frequency by monitoring individual VF channels. • Troubleshoot DS0 problems by listening to individual channels and monitoring ABCD signaling bits on all 24 channels. • Perform stress testing by transmitting and analyzing preprogrammed, long user patterns including 55 OCTET and T1 DALY. • Reduce test setup time by recognizing and automatically configuring for the proper framing and pattern.