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. It is available in either desk set or field telephone models Field models include:
- TA-1042A/U (with data connector for AN/UXC-7 tactical facsimile machine, AN/UGC-144 communications terminal, etc.)
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. 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.
The DNVT offers the following features:
- 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.
- 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.
- FM 3-04.120 ¶2-83.
- Kirsch 1981, p. 1609.
- FM 3-04.120 ¶2-84.
- FM 3-04.120 ¶2-85.
- FM 3-04.120 ¶2-86.