TN419B
The TN419B tone-clock (for non-US installations):
- Supplies Stratum 4 timing to the port network (PN) where it resides
- Derives 2-MHz and 160-kHz clocks, and an 8-kHz frame clock, from its Stratum 4 source frequency
- Produces (using European A-law companding) call-progress tones, touch tones, answer-back tone, and trunk-transmission test tone
- Supplies a ring-voltage alarm-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
