Figure 1-21. Extension service.
PART D - TELEPHONE SET TA-954/TT
36. Purpose and use. The DNVT TA-954/TT is a 4-wire telephone set which transmits and receives
conditioned diphase-modulated digital voice and loop signaling at the rate of 16 or 32 kilobits per
second (kbs). Selection of the 16 or 32 kb/s is accomplished by the use of a switch alongside the
37. Function and interface. The DNVT operates from a common battery voltage of +24 to +56 volt
appearing on the 4-wire lines. The DNVT contains built-in protection from nuclear high energy
electromagnetic pulses (EMP) and lightning. The DNVT includes an audio interface, analog-to-
digital/digital-to-analog (A-D/D-A) conversion, loop interface, signaling and supervision, power and
control. It directly interfaces with specific digital equipment.