RT1- In-Line Voice & Position Encryptor

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RT1- In-Line Voice & Position Encryptor


The RT1 provides communication clarity to frontline warfighters whilst providing commanders with vital blue-force position information. The RT1 is a high performance in-line secure digital voice modem with built-in GPS. The RT1 easily integrates with all VHF, UHF and HF radio transceivers via the audio or accessory interface. The unit is suitable for use with hand-held and man-pack radio equipment.


All radio communications are vulnerable to eavesdropping. The RT1's built-in AES encryption means that all communications are secured by a trusted algorithm. Switching between Secure Digital Voice (SDV) and analog voice (analogue SSB or FM) transmission is done by pressing the PLAIN / SECURE button (lock symbol).


The RT1 can be configured to send out periodic position reports or to send position with voice transmissions. These can be received and displayed by RT5 units and the RT COMMANDPOINT PC software.


Long-range communication is prone to interference and noise. Both digital voice and data operation benefits from superior technology and experience in HF modem design. The latest generation Vocoder-modem-combination dramatically improves voice quality in adverse channel conditions, extending the range of voice communications. Furthermore, the unit can be set-up to run in low-latency (V/UHF) or robust BLOS (HF) mode. The result is significantly extended range and increased data throughput.

RT1 Secure Voice & Position


  • AES-256 Encryption: Voice & Position Transmissions
  • 600 – 2400 bps Digital Voice Rates
  • TWELP* Vocoder
  • High Voice Clarity
  • Automatic Vocoder Rate Adjustment
  • Automatic Clear Voice Reception (FM/SSB) 
  • Best-in-class Voice Modem Performance
  • V/UHF & HF Transceiver Compatible (SSB & FM) 
  • Cross-Vendor Radio Interoperability 
  • Extended Range, including BLoS Links
  • GPS & GLONASS Support Built-in
  • Automatic Periodic Position Transfer 
  • Over-the-Air compatible with RT5 
  • RT1 Handset / Headset / Speaker-Mic Variants
  • 4.5 – 18 V DC Input with Surge Protection
  • 2 Year Warranty
  • Zeroize Function
  • Blue Force Tracking via RT COMMANDPOINT
Key Fill 256 different user selectable cryptographic keys. Optional automatic key rotation on selectable intervals (to last up to 21.3 years). New key sets can be generated via KMS-256 and loaded via CLS software which runs on a MS Windows tablet.
Key Fill and configuration happens via a Bluetooth interface
Security  Advanced Encryption Standard (AES), 256-bit key length. Key selection via keypad.
Modem High performance serial toneHF and V/UHF modem (Beyond Line of Sight [BLoS] compatible) featuring adaptive equalization.
FM squelch detect for power saving
Vocoder  TWELP: Tri-Wave Excited Linear Prediction high performance vocoder.
600, 1200 & 2400bps Low-rate Vocoder
Digital Voice 
Vocoder Rate 
End-to-End Latency
PESQ Channel Use Speech Quality Understand-Ability Limit 
SNR [dB]
Intelligibility Speaker
2 400 1.6 3.1 Ground Wave Very Good Good 6.5 0.5
1 200 2.2 3.0 Sky Wave Good Acceptable 4.0 -0.5
600 2.2 2.4 Sky Wave Acceptable Fair 0.5 -3.0


Weight 200 g with mounting strap (excludes
handset & cables)
Safety IEC/EN 60950
Size 117 x 52 x 20 mm EMC/EMI MIL-STD-461
Colour Olive Drab / Military Green Shock MIL-STD-810F: 40G, 15 - 23 ms
Mounting 1" webbing strap. MOLLE / PADS compatible Vibration Composite wheeled vehicle 10Hz – 2000Hz, @2.5g
Power Input 4.5 - 18 V DC Temperature -40°C to +65°C (operating), -40°C to +85°C (storage)
Bluetooth Key Fill & Configuration interface (via CLS) Humidity MIL-STD-810F: 0 to 90%, non-condensing
GPS / GLONASS 12 channel, -165 dBHz, active patch antenna Ingress IP67, 1m for 30 min


AA: Any 
Any Radio, Any H/Set
SC: Headset (NR) SH: H-250/U Handset (NR) SM: Speaker-Mic (NR)
RT1 Any Radio Any H/Set RT1 Headset H-250/U Handset Speaker-Mic RT1

** Note: If required, AT Comms can quote for the fitment of customer-specified connectors

Interfaces Product Variant  Description
Handset /
AA Mic / Phones
Phones: Unbalanced output, 1000 Ω / 8 Ω handset and headset compatible (configurable).
MIC: Unbalanced Input, mic bias (configurable), PTT input
Bluetooth AA SC, SH, SM Bluetooth Interface: For Configuration and FILL connection to Config Load Software (CLS)
Secure Audio AA SC, SH, SM Baseband Audio In: Un-bal. 600 Ω, –35 to +20 dBm no adjustment. Baseband Audio Out: Un-bal., 40 Ω, –20mV to +2V RMS (configurable). Keyline: Open Collector (<36 V, 200 mA).
Radio Power AA SC, SH, SM 4.5 – 18 VDC, 2000 mW max
Keypad / UI AA SC, SH, SM Individual keys: SECURE/PLAIN, Volume +, Volume -, MEDIVAC, ATTACK ALERT
Via key combinations: Zeroize, Key selection, Bluetooth enable.
Clear voice warning, Audio alerts and indication side-tones

RT1- In-Line Voice & Position Encryptor