The keys with letters are for call precedence in order from highest to lowest:
There is a pair of Velcro straps built into the phone that would allow it to be tied to something maybe even a telephone pole.
- FO = Flash Overide
- F = Flash
- I = Immediate
- P = Priority
- R = Routine
- C = Conference
55 Pin ConnectorThere is a 55 pin connector (Digital Data Port (DDP)) that may be for connecting something like a FAX, radio or data device to the terminal and it also may be for connection to an encryption device? The MS27467T17B35S 55-pin circular connector (mates with DSVT data port) might be the mating connector for the TA-1042?
There is a KG-84 to UCX-7 Cable that appears to have a connector that mates with the DDP on the TA-1042.
Signal Ground 2
Transmit Audio Shield 3
Extension Ring Output 5
Transmit Audio Return 7
Transmit Audio Input 8
TA-1035 Indicator (Signal is 0 volt output from DNVT) 9
Resync Command Input 10
Ext R1 Input (dialed digit control line) 11
Ext Off Hook Input 12
Dial Output (indicates DVNT dial state) 14
Voice / Data (selects voice or data mode of DNVT) 16
Transmit Clock Output 17
Ext R2 Input (dialed digit control line) 18
Ring / Busy Indicator Output 19
Data Device / Extension Network Power (this is a control line and is not to be used to derive power from the DNVT) 22
Data Device Off - Hook Input 24
Transmit Data Input 25
Read Dialed Digit Input 26
Extension Push-to-talk input 28
Transmit Ready Output 30
Ring Data Output 32
Ext C1 Input (dialed digit control line) 33
Extension Network Connection Signal Input 36
Data Device Connection Signal Input 37
Loop Back Input 38
Rate Change Flag Output 39
Receive Data Output 40
Ext C2 Input (dialed digit control line) 41
Half Duplex Flag Output 46
Receive Clock Output 47
Local Off Hook Output 48
TA-1042 Indicator Output (Signal is +6v, +0.8v/-0.5v, output from the DVNT) 49
Receive Audio Return 50
Receive Audio Output 51
Codewords Output (dial digit codewords from the DVNT to TCS) 52
Go On Hook Output 53
Frame Ground 54
Receive Audio Shield 55
Busy Tone Output (set when DNVT detects busy or error signals from the TCS)
The handset uses a 6 pin U-183 audio connector and may be a version of the H-350. The PTT switch is not used in normal phone operation, only when the phone is connected to a radio. If the PTT switch is pressed when two phones are connected as described below you will hear a beep and when it is released a different frequency beep.
The F91100 BER Test Set contains a cable that mates to this connector for testing end ot end BER.
Two TA-1042 DNVTs can be connected to each other and operated in the local mode. To do this:
The following current numbers are for both phones and a power supply voltage of 20 VDC.
- Set the SEL switch on both phones to LB 16 (LB 32 may reduce the range but can also be set on both phones)
- Connect the Red XMT binding posts on the remote phone to the Black RCV binding posts on the local phone
- Connect the Black RCV binding posts on the remote phone to the Red XMT binding posts on the local phone
- Connect the Red PWR binding post to on the remote phone to the Red PWR binding post on the local phone
- Connect the Black PWR binding post on the remote phone to the Black PWR binding post on the local phone
- Connect the Red PWR binding post on the local phone (total of 2 wires here) to + 20 to 60 VDC
- Connect the Black PWR binding post on the local phone (total of 2 wires here) to the DC return.
With both phones on hook the total current draw is about 10 mA.
When either phone is taken off hook the other phone rings (its RING LED flashes), the current is about 30 mA.
When both phones are off hook the current stays at 30 mA.
When one of the phones is put back on hook the other phones RING light will be on steady, indicating that the other party has hung up.
When the final phone is put back on hook the RING LED turns off.
If the pair connecting to the RCV binding posts is disconnected that phone can still ring the other phone and still hear them, but can not receive anything. This indicates there is no handshaking going on, just straight transmission.
The precedence keys (FO, F etc.) have no meaning when only two phones are being used.
If the DC voltage is reduced the current increases. This is not what would happen with a resistive load. It indicates that the phone has a switching power supply that will keep the phone going even if the Local Battery is going flat.
DIGITAL NON-SECURE VOICE TERMINAL
WITH DIGITAL DATA PORT TA-1042A/U
PART NUMBER 5285000-001
ARMY TM 11-5805-780-12&P 30 JUNE 1991 (Army Warranty) TB 11-5805-780-15 15 MAY 1992 AIR FORCE TO 31W1-2U-1461 30 JUNE 1991 MARINE CORPS TM 08789B-12/1 30 JUNE 1991 SCI TECHNOLOGY INC F04606-89-D-0097 na
The digital nonsecure voice terminal (DNVT) is a ruggedized field telephone. It is operable as a tabletop device in tents, shelters, and office environments. It also may be operated outdoors while strapped to a tree or pole. The DNVT is designed for durability to exposure of the elements during operation and transportation. Voice communication is accomplished through the handset. Digital data from an external device interfaces through the TA-1042A/U's digital data port (DDP). The DNVT transmits and receives full duplex, conditioned diphase digital voice and loop signaling information at 16 or 32 kb/s rates. The DNVT is a nonsecure telephone with no encryption capability. It digitizes voice information using continuously variable slope delta (CVSD) modulation. Digital communication transmissions, both to and from the DNVT, are accomplished using a conditioned diphase (CDP) data transmission method. This is accomplished by using the DDP. The DNVT operates in both common battery mode and local battery point-to-point mode, but not simultaneously.
The key question is can two of these talk to each other, or can they only be used to talk to a switchboard or phone system? YES, two phones will talk without a switch.
ACC Manual 33-150 Volume 3 - has some interconnect wiring diagrams, but it's hard to tell what's what. (does not include graphics)
If you have any manuals or information email brooke
Loop Signaling -conditioned diphase modulation; 8-bit cyclically permuted code words (per TT-B1-4204-0028 & TT-A3-9012-0046)
Note that the protocol is how the phone interacts with the switch. The MX/FX629 CODEC only converts the voice signals to/from digital using the Continuously Variable Slope Delta (CVSD) algorithm.
The TA-954 and/or the TA-1035 phones may only be able to work in conjunction with a digital switch, but a pair of TA-1042 phones can talk to each other. This might be used by the commander as a "hot line" to another important person. Just picking up the phone rings the other party.
Major components: RT-1539 and KY-68
MSRT Installation Kits for various models of Humvees.
FM 11-43 - Chapter 3 -
OCS - EBB - some info about digital phones
FM 44-64 - Chapt 2 -
Fort Sill - Mobile Subscriber Equipment (MSE) User Terminals -
FM 8-10-9 - Fig F-9 is UXC-7,
Transmit and receive images through the ACUS. Can be used with a DNVT with data port or KY-68/DSVT.
TM 11 5815-615-10 with change 2, 1 Sep 1987
Newcomp Systems - makes the -801 card that adds features
J1 Options for the AN/UXC-7How many pins on J1 and what do they do?
KY-68 DSVT KY-84 DLED Description Jumper Plug 6' cable 6' cable 6' cable NSN 5995-01-230-6975 5995-01-219-6770 5995-01-213-2386 5995-01-213-9648
mates with TA-1024
The TS-21 Blackjack AN/UXC-10 FAX (NSN 5815-01-478-7095) uses the same cable as the AN/UXC-7.
14 March 2023 A digital switch is now available.
Nick's Knacks: DNVT Military Phone Switch for TA-1042 -
Reverse Engineering a Cold War Military Telephone, 30:01
Introduction to the TA-1042 & TA-954.
1:35 Demo of switch.
2:08 POTS telephone without switching equipment
5:50 Digital Interface, 2 pairs,
6:46 Rob Ruark & the DVNT Switch Ver 1 with LEDs; Ver 2 with LCD
8:04 Differential Manchester Encoding (Wiki) -
11:12 Tangent Time (dancing)
11:17 Computer Engineering 101, Arduino UNO R3 (Wiki) UART (needed at 32 kHz) v. Bit Banging (OK @ 16 kHz)
15:33 Lack of
Differential Manchester Encoding in uC;
16:28 Raspberry Pi RP2040 (Wiki)
17:31 Digital Audio CVSD (Wiki) data
18:34 Control Protocol, IEEE The Digital Nonsecure Voice Terminal, cyclically distinct code words (Wiki) 23 possible code words
22:21 The Code Words
24:53 Features as of 14 March 23
28:46 For Sale on Tindie
YouTube: What's inside this old military telephone? | TA-1042 Part 2, 42:04 -June 2023
USMC - TOPIC: TA-1042 "Don't throw it away for lack of a handset retaining clip!!!" - USMC has 10,502 of these phones.
FM 100-12 - Appendix E -
"Area Common User SystemFM 11-43, Chapt 3 - Subscriber Terminal Equipment -
C-13. The ACUS is the in-theater, tactical communications equivalent to civilian phone service. The ACUS is installed and operated by the Army signal brigades at the EAC and corps levels and organic signal battalions in the divisionsí environment. The ACUS utilizes the MSE communications family of equipment that consists of a variety of multichannel radio and switching systems to form a communications network to provide bulk-encrypted (secure), voice and data, and tactical packet network switching. User owned and operated devices that facilitate connectivity to the MSE-ACUS include the TA-1042/U Digital Nonsecure Voice Telephone (DNVT) with data port; the KY-68 Digital Secure Voice Terminal (DSVT) with data port, used for above SECRET and/or special security access transmissions; the AN/UXC-7 lightweight tactical facsimile; and the AN/VRC-97 mobile subscriber radio terminal (MSRT), which provides mobile secure voice into the MSE network. MSE equipment operates at 16 Kbs and is not operationally compatible with EAC TRITAC-ACUS.
C-14. At the EAC, the ACUS uses TRITAC equipment. TRITAC is a joint communications family of equipment that uses a variety of multichannel radio and switching systems to form a network that provides bulk-encrypted (secure), voice and data, and tactical packet network message switching. TRITAC user owned and operated devices that facilitate connectivity to the TRITAC-ACUS include the TA-1042/U DNVT with data port; the KY-68 DSVT with data port for above SECRET and/or special security access; the AN/UXC-7 lightweight tactical facsimile; and for a very limited number of subscribers the AN/VRC-97 MSRT, which provides mobile secure-voice into the MSE network. TRITAC equipment operates at both 16 kbs and 32 kbs (selectable) and may be used with both the TRITAC and MSE equipment networks."
Keys:California National Guard - MOS 31U Signal Support Systems Specialist -
0 through 9 (Black) enters address (phone number)
P Enters precedence code (Priority), I = Immediate, F = Flash, FO = Flash Override, C = Conference
The PTT switch is not used for normal operation, only for Radio Wire Integration (RWI) applications
The transmit binding posts are black and the receifve binding posts are red to correspond with the phantom Common Battery (CB) operation polaritiy. WF-16 wire color coding is: green wires to Tx (Black), brown wires to Rx (Red)
The J-1077 distrubution box allows for the connection of 13 phones. Green wires to odd numbered pairs and brown wires to even numbered pairs.
General Information on Tactical Phones (DNVT) - if the field wire is connected with reverse polarity a fuse in the phone will blow requiring DS maintenance to replace.
TSEC/KY-68 operation - SVAR = SCI variable, LDX = Load X variable (M on KYK-13), LDU = load the U variable, 6.5 V Mercury BA-1372 used for memory keep alive. KYK-13 fill gun,
DNVT web page -Preparing DNVT (TA-1042) for Operations - General Tactical phone info -
This mil spec is just for the conversion from voice signal to a digital signal, it does not include the signaling protocol for the phones.
MXCOM - MX629 Delta Modulation Codec - MX619 & MX629 -AF - Computer, Network, Switching, adn Cryptographic Systems - training stuff
CML Semi - FX629 Delta Modulation Codec -
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page created 30 Sep 2001.