Abstract: Systems and methods are provided for automatically and remotely establishing a diagnostic channel between a network managed master digital service unit (DSU) and a remote fractional T1 or E1 DSU. In the preferred method, the master DSU sends a priming sequence in all of the DS0s/TS0s of the DS0/TS0 bundle intended for the remote DSU which is comprised of a two second break, followed by a relatively low frequency signal which identifies at least the diagnostic channel for the remote DSU. In response, the remote DSU sends a confirmation signal to the master over the identified diagnostic channel, after which the master DSU can send configuration information over the same diagnostic channel.

Abstract: Apparatus and methods for automatically determining the bit rate of an incoming signal are provided. The apparatus includes a counter, a logic circuit, and a histogram generating circuit. The counter counts the number of fast reference clock cycles which fit within each pulse of the incoming signal for a statistically significant number of pulses and provides indications thereof to the logic circuit. The logic circuit associates each of the indications with one of a plurality of allowable bit rates. The histogram generating circuit tracks the numbers of times the counts are associated with each allowable bit rate. In one embodiment, the allowable bit rate most often chosen is determined to be the bit rate of the incoming signal. In another embodiment, if a DDS1 line rate is determined to be the bit rate most often chosen, the DDS2 rate associated with the DDS1 line rate is provisionally selected.