connecter between FTDI rs232/USB and RJ45 cable

[deafasabat]

I am not electronically adept, to put it mildly. However, I have been trying to get CDC, and EQMOd, to recognise my mount but totally unsucessfully( a Skywatcher EQ3- PRO) and by a process of elimination have come to the conclusion the connector between the rs232/USB adapter and the RJ45 cable must be the guilty party. I have pulled the end off this to have a look at the connections and they seem to be at variance to other pieces of information I am finding. There are 3 wires coming from the serial connector end(is that a DB9?) black,yellow,green,  from pins 5,3,2 respectively. These are connected to pins 3,6,5 respectively in the RJ45 end of the adaptor. Is this correct, and if not where can I get one from that is correct?  I did buy this some while ago with RJ11 cable from an EBay site that supposedly were for serial/usb conversion, perhaps it was correct for what I wanted then, Stellarium to Meade ETX150, but it certainly isn't now.

Chris

[Dr_Ju_ju]

Are you trying to drive the mount directly or via the handset ??   the ones I make up (USB to serial adaptor to an RJ45 connector), Pin 1 and Pin 4 of the RJ45 cable connect to the GND terminal on the adaptor (orange\white & blue wires in standard wiring)

then Pin 5 (blue\white) to the terminal marked RX, and Pin 6 (green) to the terminal marked TX.

 

These I have used on both my EQ3 & AZEQ6 mounts, with no issues

[deafasabat]

Thanks for the reply. Yes I am trying to go down the EQDirect route, bypassing the hand controller.

[Dr_Ju_ju]

FYI, the adaptors I use are http://www.ebay.co.uk/itm/USB-to-Serial-TTL-Module-Adapter-PL2303-/221857377079?hash=item33a7baeb37:g:sjUAAOSwLVZV067d or variants of FTDI chipsets etc...

[deafasabat]

Sorry to sound very dumb, but I did say I was electronically inept. Are you saying that the wires from the RJ45 plug ,pins 1/4,5 and 6 connect to pins 5,3 and 2 in the db9 . Nothing is shown on either unit to indicate Rx, Tx,or Ground  so I have had to resort to the web to try to work out what is which, and I am still a tad confused. None of the wires in the assembly match any of the colours quoted by you. Sorry to be a pain!

 

Chris

[Dr_Ju_ju]

Hi Chris,

The colours I quoted, are the standard colours used in an RJ45 network connect lead. I just cut off one end and then wire (solder) it to one of the devices I linked to above. The USB end then plugs into the computer and the RJ45 plugs into the RJ45 socket on the EQ3 motor driver box, where the handset would normally plug into.

You don't need to use the DB9 to RJ11\12 lead that came with the mount, it is only needed if you want to drive the mount via the handset.

 

[Lonestar70]

17 hours ago, deafasabat said:

Sorry to sound very dumb, but I did say I was electronically inept. Are you saying that the wires from the RJ45 plug ,pins 1/4,5 and 6 connect to pins 5,3 and 2 in the db9 . Nothing is shown on either unit to indicate Rx, Tx,or Ground  so I have had to resort to the web to try to work out what is which, and I am still a tad confused. None of the wires in the assembly match any of the colours quoted by you. Sorry to be a pain!

 

Chris

Hi Chris,

Reading all of the above, I agree with Julian in that it would seem you are trying to use the handset RS232 update cable as a direct cable to your mount, unfortunately that will not work for you as a direct connection.

You could use it in conjunction with the handset by connecting the handset to the mount in the normal fashion and then connect the handset back to your PC/Laptop with the DB9 - RJ11 cable (using a USB/RS232 adaptor if your PC/Laptop is not equipped with a true 9pin RS232 port (most are not)).

You would then set the handset into PCdirect mode via the menus and EQMOD should connect... you should then leave the handset alone (don't use the buttons for adjusting your scope)

Unfortunately this method can also lead to timing errors and, as such, it is not the preferred method.

For a true direct connection what you need is an FTDI EQdirect cable which incorporates a bunch of electronics between the USB connector on your PC/Laptop and the RJ45 plug which attaches to your mount.... you don't need the handset.

If you are not that adept with electronic and soldering of connectors then I would recommend that you obtain a ready made cable, since you can very easily damage your mount with an incorrectly wired one.

A suitable cable can be obtained from here: -

http://www.astronomiser.co.uk/eqdir.htm

Scroll down to find part number 'ASTEQDF51' (second picture down + list of optional lengths).

You will also need to download the correct driver for your PC/Laptop: -

http://www.ftdichip.com/Drivers/VCP.htm

You need the top VCD driver for windows Version 2.12.18.

Hope this helps.

Best regards.

Sandy.

 

 

[ringz]

Added by mistake, I didn't read the first post properly

[deafasabat]

There appears to be some confusion creeping in here. I want to use EQDIR from laptop to mount. As previously stated. I am trying to use an FTDI usb to RS232 adapter. To use this I need to connect the 9 pin plug on the FDTI adapter to an RJ45 cable  with RJ45 plugs at both ends. It is this connection between the adapter and the cable that is causing problems. (Can I buy one ready made that would connect to the FTDI adapter and terminate in an RJ45 plug? Not seen one. Would all of this.)

I have now acquired a semi pre-wired adapter where the wires are already connected to the RJ45 socket end of the adapter and need connecting to the rear of the serial socket. The colours do not match those previously given as the norm for RJ$% cabling, so all I can go on is the actual pin positions. So if someone can simply tell me which pin number joins to which pin number I would be obliged. 

The diagram on the EQDIRECT page of the EQASCOM site shows the wiring of the RJ45 plug at the mount end, which I assume is the same as athe adapter end, but which pin number the connects to which pin number at the back of the 9 pin serial plug?

I have attached a picture of the items I want to use, showing the 2 parts that need to be joined together

Chris

 

[Lonestar70]

Hi Chris,

The usb/rs232 adaptor you have will not be suitable for your mount... it contains a voltage level converter to produce +/- voltages suitable for rs232 functions.

This voltage can be as high as +/- 25v... which will produce severe damage.

Even at the minimum output of +/-5v (see attached data sheet) it will damage your mount since it's inputs are rated for 0v - +5v TTL levels only... a -5v signal voltage will not be tolerated and you will damage the input stage on your mount mother board.

The device I specified in my previous post is designed specifically for TTL output voltage levels and is the correct device for your mount.

I hope this helps.

Best regards.

Sandy.

FTDI DS_US232R-10_R-100-500.pdf

[deafasabat]

Thanks very much, I said I was electronically inept! I was aware of the Astronomiser cables but wanted to go down the USB/RS232 route for the ability to use longer cables, but this seems to cater for that to an extent.  Thanks for your help.

Chris