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DIY EQDirect USB cable for EQMod


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This is more of a late night sanity check than a question so I hope folk can help.

I'm finally getting back setup and have my new EQ6 board that comes with USB and Screw on power connectors...so a bit of an upgrade.  But I'm a little confused regarding what is needed in the EQDir department.

Now, I know I could use the on board prolific drivers and just connect via USB, but I've heard about reliability issues using the prolific chip and would like to make a new cable to replace my previous D-sub one.

Trouble is I'm not 100% convinced I'm looking at the right instructions because the EQmod page here: https://eq-mod.sourceforge.net/tutindex.html only seems to have the EQ6 connecting with the D-sub, not the new RJ45 handset connector that the new board has.

The new board is an MC015 which I think I'm right in saying is the same as in the  HEQ5 / AZEQ6-GT, just with a different faceplate.  So I THINK I need to take my FTDI TTL232R cable and solder:

  • TTL232R Black wire (GND) to Blue (Pin 4)
  • TTL232R Yellow wire (RXD) to Blue/White (Pin 5)
  • TTL232R Orange wire (TXD) to Green (Pin 6)

The reason I'm checking first is because the diagram on Page 17 of the AZEQ6 manual here: https://www.skywatcheraustralia.com.au/wp-content/uploads/2016/12/AZEQ6.pdf  have TXD and RXD the other way around....and I've learnt that when in doubt ask!!

One other question is should I really now be using a 3.3v signalling cable instead of the standard 5v TTL232R?

I appreciate any comments,


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Your wiring colours are correct and are what I've used for several skywatcher mounts including the AZEQ6. In serial comms the TXD of one device connects to the RXD of the other device and vice-versa so the AZEQ6 manual is compatible with your wiring. 🙂 You're fine using 5V TTL232R as the 3.3V interfaces currently used work with 5V without problems. Not all mounts are 3.3V though it seems to be more common now. My new EQ8-R is still 5V though.


Edited by symmetal
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No need to make an EQDIR cable with any Skywatcher mount that has a USB -B type socket.  Just use a normal (or active if over 5m) USB A-B cable between the computer and mount.  You will need to install the Prolific 2303 driver for the chipset from Skywatvchers website if running windows on the PC.  Plugging in the USB cable with the mount powered up will produce a new com port available on the computer, which needs its speed set to 115200 baud (via the properties in device manager)

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If you do want to make and use an EQDIR cable, then personally I would used the 5v TTL level 232 cables from FTDI.  The confusion you mention is probably do to the fact that TX out from the cable will be RX in on the micro controller, and vice versa

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