Sysop Registry


FlexNet driver documentation
DG1SCR - driver for the DG1SCR DSP board


    Driver for the DG1SCR DSP board.

    This driver allows DG1SCR's DSP board to be used either as 1200 baud AFSK modem or as 9600 baud FSK modem, compatible to the G3RUH standard. The board works as a modem frontend, sending a serial bitstream to the PC, which then decodes it (HDLC protocol). With 9600 baud, the analog output MUST be filtered with an analog filter!

    Starting with newer versions of Jürgen's monitor EPROMs, RTS is used for hardware handshake and can no longer be used as PTT signal.

Command line parameters:

    dg1scr [-c:<com>]

    -h, -? description of the parameters
    -c the COM port number
    -b, -p base address of the serial interface (if -c is not used)
    -i the IRQ number (if -c is used, -i must be placed afterwards)
    -d invert DTR (DTR serves as the reset line for the DSP)
    -lo left output attenuation (0..95dB)
    -ro right output attenuation (0..95dB)
    -o output attenuation of both channels (0..95dB)
    -lg left input gain (0..23dB)
    -rg right input gain (0..23dB)
    -g input gain of both channels (0..23dB)
    -m use mic input
    -l switch off line out
    -he switch off headphone out
    -s switch off speaker out

    The 9600 baud modem is sensitive to DC levels at the input. Make sure that the receiver signal is centered around ground!

PTT connection


  • Calibration finishes with some delay (maximum about 45secs at 1200 Baud)
  • Measurement of the TX delay of other stations is not supported
  • The 9600 Baud modem requires an analog filter, because the computing power of the DSP did not suffice for a better digital one
  • The 20dB amp at the mic input is switched off. This is not possible on pre revision E codecs. (the codec revision is displayed at the start of the driver)

Thomas Sailer <sailer@ife.ee.ethz.ch>
last updated:

pages created by Gerald Schreiber, dl9fck, last updated: March 2001