TN768
The TN768 is replaced by the TN2182 tone clock - tone detector and call classifier circuit pack.
The TN768 tone-clock:
- Supplies Stratum 4 timing to the port network (PN) where it resides
- Derives 2-MHz, 160-kHz, and 8-kHz clocks from its Stratum 4 source frequency
- Produces (using North American mu-law companding) call-progress tones, touch tones, answer-back tone, and trunk-transmission test tone
- Has a ring-generator detection circuit
- Can transmit clock signals and tones on time-division multiplex (TDM) bus A, on TDM bus B, or on both buses
- Allows the system to control which PN's tone-clock provides clocking for the entire system
