The 1645A Data Error Analyzer quickly isolates data communications link problems through six simultaneous measurements. During tests, the 1645A can be left totally unattended because it automatically maintains synchronization even in the presence of dropouts. Bit-error and block-error rate tests are auto ranged and displayed directly on an LED readout, there is no need to perform any calculation. Additionally, the 1645A measures jitter or total peak distortion (the sum effect of jitter and bias), counts the number of times carrier loss or dropouts occur, measures data error skew and counts the number of clock slips resulting from phase hits or modem synchronization problems. Pinpoint excessive turnaround times and wrong voltages with the 10235A.