Frequently asked questions

PACTOR (Packet Teleprinting Over Radio) is a digital transmission protocol for shortwave radio. It allows reliable data transmission (email, weather bulletins, status messages) over thousands of kilometres – entirely independent of internet, mobile networks and satellites. Typical users include offshore yachts, commercial shipping, government, disaster relief and researchers in remote regions.

SCS (Spezielle Communications Systeme GmbH & Co. KG) is the manufacturer of the PACTOR technology, based in Hanau, Germany. WiMo Antennen und Elektronik GmbH (Herxheim) has taken over distribution and logistics for the P4dragon modems. SCS remains the technology brand of the PACTOR component; WiMo is the umbrella brand and central sales partner.

Winlink is a software / network – an HF modem is still needed to actually transmit data, and PACTOR is the most robust widely used protocol for that. Compared to satellite services like Starlink/Iridium, PACTOR is significantly cheaper to operate (no ongoing fees, no subscription), runs completely decentralized, and is not dependent on a single provider. The trade-off: much lower throughput – PACTOR is not a replacement for streaming, but for safety-critical text and status data.

Currently shipping is the P4dragon series: P4dragon DR-7800 (flagship with OLED display, optional Ethernet/Bluetooth) and P4dragon DR-7400 (compact entry model). Both devices are software compatible with the older PTC-II / PTC-III modems. Available from WiMo or an authorized dealer.

Both devices use the same quad-core DSP and support the full PACTOR feature set. The DR-7800 additionally features a high-resolution OLED display with waterfall and spectrum view, two transceiver ports, optional Ethernet and Bluetooth – designed for professional fixed installation. The DR-7400 is more compact, lighter (450 g) and focused on the essentials; ideal for yachts, mobile applications and as a low-cost entry.

Yes. The P4dragon modems are software compatible with the PTC-II devices, so existing applications like Airmail, RMS Express, Winlink Express, Alpha or Sailmail continue to work. The radio ports are pin-compatible as well – re-plug, power up, done.

Any common SSB transceiver with a 2.4 kHz IF bandwidth. Through the internal multi-level interface (V24, TTL), the modems are compatible with Kenwood, Icom and Yaesu transceivers as well as many other models. For modern radios with built-in USB audio codec (e.g. ICOM IC-7300) the cabling is particularly simple.

Max. approx. 3 W at 13.8 V supply – an important advantage in off-grid applications (yacht, emergency power, solar). Supply voltage range: 10–28 V (DR-7800) or 10–27 V (DR-7400).

Current prices and availability are provided by WiMo or by an authorized dealer in your region. For larger volumes, government and critical-infrastructure orders please contact our sales team directly.

No. Updates to the standard firmware for the P4dragon series are free and can be installed via the user interface or the P4config tool. Chargeable are only the optional features 2G ALE and AES-256 encryption – both are unlocked via a feature license.

We recommend the current P4config tool (download in the download center). Procedure: 1) Connect the modem via USB. 2) Start P4config. 3) Select the current firmware (e.g. dragon_fw_2_45_00_dr7.zip). 4) Run the update and do not power off the modem during the process. Detailed instructions are provided in the matching update info PDF.

In the download center under "General". For Windows use the current SCS USB driver installer, for macOS the SCS USB Serial Driver. Under Linux, current distributions detect P4dragon modems as a USB serial device out of the box.

2G ALE (Automatic Link Establishment, MIL-STD-188-141) performs a fully automatic analysis of current propagation conditions on the shortwave bands and selects the optimal frequency / band for the link. No more guessing the best channel – the user experience is comparable to a turn-key radio solution. ALE and PACTOR are switched automatically by the modem.

The AES-256 option implements the AES standard directly inside the modem. It enables end-to-end encryption of PACTOR connections at modem level. A formal certification (BSI, NATO Restricted etc.) is not currently in place – this needs to be assessed per use case. For higher protection requirements we recommend combining with an additionally approved Layer-2 / Layer-7 encryption.

Because it can be operated fail-safe, internet-independent, decentralized and without ongoing fees. A PACTOR link still works when fibre, mobile and satellite have failed or cannot be trusted – a classic resilience building block for crisis communication in critical sectors (energy, water, health, government).

Yes – under the dedicated solution brand KRITIS-KOM WiMo bundles turn-key packages consisting of P4dragon modem, transceiver, antenna, power supply, training and maintenance – specifically for government, disaster relief and NGOs.

For government and emergency-services frequencies the allocation is handled by the responsible regulator (in Germany: BNetzA, in other countries the national equivalent). In amateur radio, PACTOR modems can be used with a valid amateur radio license. We're happy to assist with clarifying the regulatory framework.

Availability of the P4dragon modems has been secured long-term through the takeover of the SCS portfolio by WiMo. Firmware updates, repairs and spare-parts supply are continuously ensured.

Repairs, warranty cases and returns are handled centrally by WiMo. Please start the process through the WiMo returns portal – there you'll receive an RMA number and the correct shipping address. Please also refer to the SCS Limited Warranty Statement.