• Max. 10500 bps net
  • 2x faster than P3
  • Backward compatible
  • 2400 Hz bandwidth
  • Highly adaptive
  • 10 Speedlevels
  • High interference immunity
  • 6 auto-notches
  • Adaptive equalizer


Operating Modes:

  • PACTOR-4
  • PACTOR-3
  • PACTOR-2
  • PACTOR-1
  • 2G ALE, MIL-STD-188-141 (optional)
  • Packet-Radio
  • Robust-Packet (RPR)
  • APRS
  • FM-FAX (Rx only)
  • RTTY (Rx only)

New: P4dragon 2G ALE and AES Firmware

2G ALE, the de facto standard for optimal frequency / band selection, is now available as an integral firmware update to our P4dragon DR-7X00 HF modems. 2G ALE provides a complete automatic analysis of current propagation conditions on the shortwave bands, which relieves the user from having to guess the best channel when seeking to connect to a distant station.

The 2G ALE function has primarily been implemented for ease of use of PACTOR operation, i.e. as an automatic frontend for PACTOR connections. The switchover between the two protocols, 2G ALE and PACTOR, is carried out automatically by the modem.

The Advanced Encryption Standard (AES) option allows state-of-the-art data encryption, now embedded directly in the SCS HF modems - i.e. native encryption of PACTOR connections at the modem level.

The ALE firmware provides 100 free ALE trial links before an ALE license is required.

For an in depth description please have a look at

The P4dragon DR-7X00 Modems

The SCS P4dragon DR-7800 is our superior class  short-wave modem for PACTOR-4. P4dragon stands for the most ingenious data transfer algorithms and the highest computing power possible in PACTOR controllers of the 4th generation.

Due to its compact construction and focussing on the most important features, the P4dragon DR-7400 offers a lower-priced entry to the P4dragon modem class.

The fast quad-core DSP used in the DR-7X00 modems enables for the very first time, a high data rate, approaching very close to the Shannon limit, as well as an extremely high immunity to interference. PACTOR-4, with its 10 speed levels and adaptive equalizer, adjusts itself ideally to varying channel conditions, and guarantees reliable data transfer even under very poor propagation conditions. Due to this high reliability, P4dragon modems allow transmission of safety relevant data via shortwave, and provide an excellent value for money when compared to many satellite services.


Spezielle Communications Systeme GmbH & Co. KG

Roentgenstr. 36

D-63454 Hanau, GERMANY