Can anyone help me on this Nexstar data cable wiring

hommel · Post by **hommel** » Tue Apr 03, 2007 11:17 pm

I want to update the firmware on my Nexstar hand controller (HC) and need a
DIY programming cable, the question is the RJ45 connector to my HC has only 4 connectors, whereas the schematic diagram (on celestron website) shows the serial cable (DB-09) requires 5 connectors eg pin 2,3,5,7,8

Pin 2 --> Data Terminal Ready
Pin 3 --> Transmitted Data
Pin 5 --> Ground
Pin 7 --> Data Set Ready
Pin 8 --> Clear to Send

Which cable can I omit so that I can use the RJ45 4 pin connector that fit my HC, as there's no 5 connector available anywhere? :?:

Added: The schematic on celestron website eg 8P8C doesn't fit my nexstar hand control, i need a 4 pin type, I have to omit one pin but dunno which one.

Meng Lee · Post by **Meng Lee** » Tue Apr 03, 2007 11:24 pm

Erm, I am not too good with this wiring thing. Here is a commercial cable if you don't want to take risks.

http://www.telescope.com/shopping/produ ... oductID=96

then if you only have usb ports then can get a USB to Serial (DB9) adapter.

hommel · Post by **hommel** » Tue Apr 03, 2007 11:26 pm

Meng Lee wrote:Erm, I am not too good with this wiring thing. Here is a commercial cable if you don't want to take risks.

http://www.telescope.com/shopping/produ ... oductID=96

then if you only have usb ports then can get a USB to Serial (DB9) adapter.

That cable retails for $49, don't wish to spend that amount on a cable i use only once :? On the Orion website, the DB9 has 5 pin out to the RJ45 which become 4 pin ?

Meng Lee · Post by **Meng Lee** » Tue Apr 03, 2007 11:30 pm

if you can find out the pin out on the DB9 as well as on the RJ45 then I think just 6 dollars should be able to make the cable.

Off topic: The skysensor autoguider port turned into ST4 autoguider pinout is less than 3 dollars of equipment from Sim Lim Tower, once you know the pinout of both ends.

yanyewkay · Post by **yanyewkay** » Wed Apr 04, 2007 12:08 am

bro, try this
http://www.nexstarsite.com/PCControl/RS232Cable.htm

only pin 2 3 and 5 are used

hommel · Post by **hommel** » Wed Apr 04, 2007 12:41 am

yanyewkay wrote:bro, try this
http://www.nexstarsite.com/PCControl/RS232Cable.htm

only pin 2 3 and 5 are used

Thank you so much! Thats what i'm looking for

Luckily for me i didn't make a guess and remove the ground pin.