                           *** 2004-01-05 ***
                         *** PCR1000 / W4SM ***
 
 Shortly after getting an Icom PCR1000, I found that several folks had 
 reverse engineered the command codes and made them available on the
 internet.  At about the same time, I began looking at interfacing the 
 PCR1000 with my MKII G3RUH 400 bps PSK telemetry demodulator for AO-40.
 Because the telemetry stream is PSK, very tight frequency control is 
 necessary to get proper decoding.
 
 The MKII demodulator has a feedback loop to the receiver based on 
 "mike-click" type tuning, which grounds (or pulls high) two lines,
 one for "up" and one for "down".  However, the PCR1000 has no direct 
 capability for mike-click tuning.  Given the ability to fully program 
 the PCR1000 by serial port, this is not a major problem.
 
 The program in this zip file, PCR1000.exe, is a simple but reasonably
 complete control program for the Icom PCR1000 receiver.  It does not
 include the "scope" functions.  Most importantly for the above, this 
 software continuously monitors the status of COM line 1 (DCD) and COM
 line 8 (CTS).  The construction of a simple adapter box as seen in 
 adapter.jpg (wiring schematic in adapter.gif) allows these lines to be
 normally pulled high through 10k resistors, but grounded by the G3RUH 
 demodulator to signal "up" or "down" frequency adjustments.  The software 
 also allows you to set the amount of up/down increment.  So far, 20 Hz 
 appears to work very  well.
 
 With the combination of this software, a G3RUH demodulator, an adapter 
 box, it is easy to maintain rock solid telemetry lock for an entire pass.
 
 The only "down side" to this approach is that it requires two serial ports,
 one for the Icom PCR1000 and one for the G3RUH demodulator.  USB to 
 serial adapter cables have been tested and work fine for either connection.
 
 
 
 Usage notes:
 ------------
 The software is simple and should be self explanatory.  When the external
 speaker jack is plugged into the PCR1000, the internal speaker is muted.
 Therefore, you may unplug this jack and tune in the modem based on entering 
 an approximate frequency and tweaking to ear using the up/down increment 
 buttons in the software, or you can tune with the jack in place and the 
 speaker muted using a good starting estimate and the carrier/clock LED's on 
 the demodulator.
 
 
 DISCLAIMER
 ----------
 Most PCR1000 code "hackers" strongly suggest backing up the ROM-based 
 configuration file in your PCR1000 before using "un-approved" software.  I 
 encourage this.  A "Google" search for:  PCR1000 will find multiple sites 
 with this software available for free.  It takes only a few seconds to 
 make a backup copy of your configuration file.
 
 Having said the above, however, I believe that most problems with ROM corruption
 have come from inadvertantly sending commands to the ROM, possibly due to a 
 baud rate mis-match between the ICOM PCR1000 and the control software.  This 
 program, unlike others, does not change the "wake-up" baud rate of the PCR1000
 from its value of 9600 and the software includes no ROM commands.  Therefore,
 I believe it is highly unlikely that this software can corrupt the on-board
 ROM.
 
 ---Stacey, W4SM
 