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FLDIGI Driver for BPQ32 switch.

FLDigi Driver

This driver allows BPQ32 to use FLDigi, a multimode Sound Card Modem, in ARQ mode. The protocol used is compatible with FLARQ, and connects can be made either between BPQ systems, or to/from FLARQ. The interface can operate in two modes "KISS" and "RAW". KISS is a bit more efficient, but is not compatible with FLARQ, so to connect to an FLARQ station you need to switch to RAW mode. See below for details. The system will respond to calls in either mode.

FLDIGI Configuration.

BPQ uses the KISS interface in FLDIGI. This has to be enabled using the Configure/IO Menu

"Dual Port" must be checked. Normally "Enable CSMA" and "Enable Busy Channel" should be unchecked. as BPQ handles Buay detect. If you want to run FLDIGI and BPQ on different machines, specify the IP address of the BPQ machine instead of

BPQ Configuration.

The driver is defined to BPQ32 with DRIVER=FLDIGI. A typical configuration is:

  ADDR 7342

Use the ADDR command to define the IP address and Port of FLDIGI, and an optional PATH to FLDIGI.exe. If PATH is omitted, bpq32 won't start FLDIGI, and you will have to run FLDIGI before starting bpq32.

For example


Note that two ports are used, one for eac direction of traffic. Data a sent to FLDIGI addressed to the specified port, and reponses are expected on the next higher port (7343 with the abouve example)
Other possible configuraton parameters are:

Sets the acknowledge timeout. Default is 5 seconds.

Sets the retry count. Default is 6

Sets the Window Size (similar to MAXFRAME in ax.25). Default is 16

Sets the Modem and Centre Frequency to return to after each connection. Specify as Name/Freq.

The modem logs connects to the Nodemap if you have specified a LOCATOR in your BPQ32.cfg. If you specify UPDATEMAP, stations heard will also be sent to the map.

The protocol operates a sliding window, with selective repeats of missed frames, so normally sending fairly large numbers of small frames in a burst is most efficient. The default PACLEN and WINDOW of 64 and 16 are ok for reasonably fast modes, but could result in very long trasmissions with slower modems. Having a very short PACLEN will increase the protocol overhead, and having too short a burst length will slow the overall transmission down due to the extra link turnrounds and ACK delays.


To make an outgoing call, first use the ATTACH command to allocate the FLDIGI port. You can then use the following commands:

MODEM ModemName - Selectes the specified modem - eg MODEM BPSK250
FREQ n - Sets the centre frequesncy - eg FREQ 1500
SQUELCH ON - Enables Squelch
SQUELCH OFF - Disable Squelch
SQUELCH n - Set Squelch Level (n = 0 - 100)
MODE RAW - Sets interface to RAW mode, normally used to connect to FLARQ
MODE KISS - Sets interface to KISS mode, nurmally used between two BPQ stations. This is the default
C CALLSIGN - Initiates an ARQ connection to CALLSIGN

For axample, a Connect Script for BBS forwardinging in BPSK250 mode could be:


Exchanging Mail with FLARQ.

You can send plain text messages composed using the FLARG "Compose" menu to a BPQ BBS. As FLARQ doesn't have an interacive mode you can't request messages using the normal BBS commands, but if you send a file called "BBSPOLL.txt" to the BBS it will be interpreted as a reverse forward request. The file can be empty.

You can also forward from BPQ Mail to FLARQ. The Connect Script must select RAW Mode and tell the BBS is is connecting to FLARQ. EG

att 10
mode raw
c g8bpq

John Wiseman GM8BPQ/G8BPQ
Aprol 2014