[rcheshire (Rowland)]

I have a 20 year old Takahashi EM-200B mount to which I would like to hook up ST-4 guiding through the 8 PIN MINI DIN hand controller connector. The mount does not have a guide port and I cannot lay my hands on one of the add on interfaces that Takahashi stopped producing in 2009.

This mount has excellent unguided tracking but I would like implement guiding all the same.

The hand controller does the usual stuff. Hi speed, lo speed, RA and DEC reversal and the RA and DEC pushbuttons.

Below is the pinout. Is this a standard 8 PIN DIN pinout for ST4? In that the pin numbers do not match the 'standard' RJ12 pinouts of which there are two versions. Need to make up a cable RJ12 to DIN.

Another complication is the mount +ve ground circuit. Clearly, interfacing something like a Lacerta M-GEN MII which has a -ve ground seems like an insurmountable problem.

Tak EM-200B Hand Controller Pinout - DIN MINI 8 PIN

1 - HI SPEED SLEW LED INDICATION
2 - HI SPEED SWITCH
3 - +VE GND - Note 2 and 3 connected
4 - RA
5 - RA
6 - DEC
7 - DEC
8 - NC

4 and 5 through RA direction switch to pushbuttons
6 and 7 through DEC direction switch to pushbuttons