Gemini 1 Serial Cable wiring
The Gemini 1 Serial Cable Losmandy Part number "GCC" was on Losmandy Web site accessories page about 3/4 way down.  But is is no longer listed.

The Gemini 2 Serial Cable Losmandy Part number "GCC Gem 2" is on Losmandy Web site accessories page about 3/4 way down.  I recommend you purchasing these cables instead of making your own.  Here is a Picture of another way to make it courtesy of Losmandy.
Please note that the 4 Pin Telephone connector for the Gemini-1 is a RJ22. It is much narrower than a standard 4 pin telephone connector. It is the size of what telephone companies used to use to connect to handsets.


The telephone connector for the Gemini-2 is a RG12 or 6C6P connector.

DB9 for G1          RJ22 for G1
short pins 1, 7 & 8 together, and 4 & 6 on RS232 connector together.

Follow the color codes for the Gemini 1 RS232 cable wiring
The telephone plug shown should be a RJ22 which is narrower than the standard RJ12 plug.
The RS-232 connector is a Female DB-9 connector.


Gemini 2 Serial Cable wiring Mode 1 and 2

DB9 for G1      
short pins 1, 7 & 8 together and 4 & 6 on RS232 connector together.

Follow the color coded for Gemini 2 RS232cable wiring
This is for mode 1 and 2 jumper setting (see Serial Port Modes)
One way to do this is to use a DB9-F to RJ12 adapter (see drawing)
Notice the two center pins of the RJ12 plug are connected together,
and get routed to pin 5 of the RS232 DB9F plug.
The RS-232 connector is a Female DB-9 connector.
The telephone connector is a RJ-12  6C6P connector.

This DB9 pin connector goes into the computer, and the RJ12 goes into Serial Port 1/Graphics HC


Gemini 2 Serial Cable wiring Mode  3

DB9 for G1    

Follow the color coded for Gemini 2 RS232cable wiring
This is for mode 3 jumper setting (see Serial Port  Modes
The RS-232 connector is a Female DB-9 connector.
The telephone connector is a RJ-12 connector.
Please note that the GPS supplied by Losmandy for the Gemini-1 will not work on the Gemini-2. It can be modified by cutting off the connectors and putting on the correct ones. You can search the user groups for these instructions. I don't have either version, so no instruction are given here .