DNVT
The Digital Nonsecure Voice Terminal (DNVT) is a telephone set which transmits and receives conditioned diphase modulated data at a signaling rate of 16 or 32 kilobits per second (kbps) over a 4-wire interface.[1] It is available in either desk set or field telephone models[2] Field models include:
- TA-954/TT
- TA-1035/U
- TA-1042A/U (with data connector for AN/UXC-7 tactical facsimile machine, AN/UGC-144 communications terminal, etc.)[3]
Pairs of TA-1042A/U DNVTs may be used in local battery (LB) mode as simple field phones, without requiring connection to a telephone exchange. The TA-954/TT, however, must always be connected to a telephone exchange as it does not support direct DNVT-to-DNVT connection. When the TA-1042A/U is operated in local battery mode, a power source of 24-56 VDC must be connected to the PWR binding posts on the right side of the phone, with positive voltage connected to the red post.
When connected to a telephone exchange and configured in common battery (CB) mode, the DNVT receives 24-56 VDC phantom power from the telephone exchange over the send/receive line pairs.[2] Positive voltage is applied to either or both of the red RCV terminals, and negative voltage is applied to either or both of the black XMT terminals.
(TBD: Can the TA-1035/U be operated without connection to an exchange? Can either the TA-954/TT or TA-1035/U be powered in LB mode?)
The DNVT offers the following features:[4]
- Digital telephone/data set for mobile subscriber equipment (MSE) and TRI-TAC systems.
- Full duplex voice or data communications.
- Push-to-talk (PTT) for combat radio net interface.
- Standard four-wire loop interface.
- Mean time between failures (MTBF): 150,000 hours.
- Automatic tracking of 16 or 32 kbps switch loop rate via autobaud feature.
The DNVT has the following specifications:[2][5]
- Data rates of 16 or 32 kbps synchronous or up to 2400 bits per second asynchronous. (TBD: Does this only apply to the TA-1042A/U?)
- Loop interface: four-wire line, up to 4km of WF-16/U field wire.
- Line impedance: 125Ω ±10% resistive.
- Operating voltage: 24 to 56 volts DC.
- Audio codec: continuously variable slope delta modulation.
- Signal format: Conditioned diphase at 16 or 32 kbps.
- Codeword format: Cyclically permuted 8-bit words.
- Output level: 3V peak to peak.
- Input level: between 150 mV and 4V peak to peak.
Related Files
TTC-39 TRI-TAC family brochure from GTE Sylvania
Notes