connect TTL output autoguiders directly to Gemini.   Refer to Appendix 8.6 for 

more details. 

If RA calibration works but Dec. does not, check the backlash in the Dec. gear. 

Set the TVC or increase the autoguider' s hysteresis setting. 

7.1.13  Gemini Displays  Autoguider Error  

This message indicates that Gemini received contradictory signals (RA+ and RA  

or DEC+ and DEC ) at the same time. If this happens occasionally, it can be 

ignored. Otherwise check the cable from the autoguider to the Gemini and keep it 

as short as possible. Do not use a twisted cable; it could induce spurious signals 

from one wire to the other. 

7.1.14  Serial Communications Problems 

Ensure that you are using the correct cable between Gemini and the PC or GPS 

receiver.  Refer to Appendix 8.5 for details.  

Start Gemini in Debug Mode and look at the information buffer to see if data is 

actually being received from the PC.  Refer to section 7.2 below.  

If you are using a PC with a fast CPU and buffered serial I/O circuitry, the 

microcontroller of the Gemini system may not be fast enough to receive and store 

all characters sent to it.  Check the setting of the communication port of your PC 

and disable the 16550A serial controller' s FIFO.  You can try to use a smaller 

FIFO send buffer first.  

7.1.15  "CMOS reset" Message upon Startup or Incorrect Date/Time 

The CR2032 Li battery was exchanged or is low.  Power off the Gemini and open 

the Gemini electronics unit.  Replace the CR2032 battery with a fresh one.  After 

you power up the Gemini again, you will see this message.  Use the   Setup   menu 

to set all of the appropriate settings for your mount (see chapter 2).  If the problem 

persists, contact your dealer. 

7.2  Debug Mode 

If you have problems with the serial link to your computer or your planetarium software, 

you can press one of the Hand Controller keys while powering up. Doing this will put 

Gemini into "Debug Mode" and show all commands that are received from the PC in the 

Information Buffer. You can scroll through this buffer with the "Show Information" 

menu item. You should see the commands sent by the software (omitting numerical 

values), that are ASCII characters (e.g. ":GR#:GD#").  If not, the serial link is not 

operational. 

The phrase "Debug Mode   is appended to the welcome message when Gemini is started 

up in Debug Mode.  

Gemini Users Manual 

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