Is it possible to use a GAZ4 with a CP705?

Yes. The Gaz must have a selectable circuit board to allow it to receive data at 9600 baud.

You can solder a jumper on older circuit boards with a switch.

Normally this ends up being a pain. Run the 705 into software and out to the display.

Also, you can use a D-line display that has selectable baud rate in the firmware.

Yes
Configure your 705 to display to an Alge ( by direct connection) set the thumb wheel switch on the Gaz to 1.The Gaz should have a toggle switch that will select 9600 or 2400 baud.Try both settings, in my experience it doesn't matter.To set up the 705 to out put to a display follow the instructions in the manual, and don't rush, it is easy to omit a key entry and not accept the changes.If you don't have manuals for the Gaz or the 705 they can be downloaded from the net.

Dave Webb