EQdirect

[libraryman]

Hi, i am attempting to make up my own TTL-232R EQdirect cable...i need a little assistance identifying the TTL232R component inside the USB cover!!!

attached are a couple of pics showing 3 types of TTL 232 USB innards....

I know what connections i need to use and have made up a cable shown with Black shrink wrap...but it is slightly different than my current broken eqdirect cable..

I accept it may not be an easy question but if someone is able to shed light on these, it would be appreciated.

My original EQ direct cable is shot...the item i am replacing it with appears to have identical components..its just ver 4 as opposed to ver 6...and the chips are on each side rather than on one side..

Ray

 

[Dr_Ju_ju]

I've made one using this http://www.ebay.co.uk/itm/231609039965?_trksid=p2060353.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT which I've modified by removing cable & replaced by a long RJ45 network lead...  (the plastic case is just clip together)

Note this device uses the 3.3 volt control signals required by my AZ-EQ6 mount, I'm not sure about your EQ8 mount if it uses the same signal voltage or uses 5 volt instead...

[Zakalwe]

3.3v for the EQ8, I believe.

[libraryman]

Cheers for the link.... after i posted, i fitted the one that i had made up, it works o.k...i just wasn't sure and caution got the better of me.....if i remember correctly it used the same type as your link points to, I'm not sure if its 5 volt or 3.3 volt but it wont matter to the mount because its 5 volt tolerant..

Just out of interest.....if you can recall, is the internal board the same as the one in the pic with the black shrink tube on it?

Ray

[Physopto]

FTDI chips did not work for me with the EQ8. The EQ8 works with both 3.3 and 5 volt chips. I used the Prolific 5 volt chip  afterwards without problems.

Derek

[libraryman]

Hi Derek, just for my education... Have you a link to the prolific chip that you use..

I admit that I don't know the difference between them other than a guess that they use different drivers!

I have only enquired about the ftdi type..

My mount is up and running again but its in my interests to learn or try to understand the difference between these chips.

Ray

[JamesF]

From memory the Prolific part you want is the PL-2302.

James

[libraryman]

Hi James, thanks.....I think I see the difference between the prolific type and the ftdi.....if I am correct; one uses the D9 type sub and the ftdi uses the RJ11....connector.....if I am correct then I am learning something!

In any event the eq direct cable I've made up is working so I've no need to change it..

Looking at the data sheet for the ftdi TTL- 232r 5volt PCB .....far left in the bottom photo.....it is physically different than the one in my original eqdirect cable, because its a pcb....apparently it can be fitted into a moulded usb cover!!

the data sheet tells me which of the pads are txd rxd & grd so I understand that.

All this info may in due course provide someone else with the means to make up their own eqdirect cable.

Ray

[JamesF]

I think you'll find both chips wired up to all sorts of connectors to be honest.  The D-sub 9 connector used to be common if you didn't need all the possible connections supported by RS232 and was common on PCs when they used to support serial devices natively.  RJ connectors have become more common over time though.  I've sometimes seen them used in combination with D-sub 9 and D-sub 25 connectors that have an RJ socket in the back so you can switch between connectors depending on what's available at the remote end.

Fundamentally there's not a lot of difference between the two.  They both provide a USB interface to an RS232 port.  The internals of the chips are different and therefore they require different drivers, but beyond that there's probably little to tell them apart.

James

[Physopto]

James is correct as far as I can tell . EQ6 used to be d sub  but EQ8 is RJ connector. The original EQMOD cable had a box in the middle with the electronics in it. It was USB to box then box to mount via D sub. With the advent of micro electronic it was changed to the electronic module being in the USB plug. I believe the EQ5 had a RJ plug at the mount. The EQ6 was d sub then the EQ8 came out with RJ at the mount. The EQ8 was designed to backwards compatible and so can take either 5 volt or 3.3 volt. I made up my cables, and several due to problems with the FTDI modules. I never got to the bottom of it FTDI were of no use. they promised to look into it but did nothing. I won't buy from them again! I wasted a lot of my time and money. I have stuck with Prolific without problems since then. It would have been nice if the Prolific chips remembered the COM port but they don't. That was the only good bit about the FTDI chips.

It may be down to  a production run of the EQ8 control boards, I cannot be sure. Other people have had some success with FTDI. When I had the EQ6 eqmod could find the com port with ease. with the EQ8 it has never found the com port. It is not a problem because you just set the port manually and it works fine.

Derek

[JamesF]

FTDI always used to be my preferred manufacturer for USB<->serial interfaces because they always seemed to be rock solid, so I'm surprised you had problems with the EQ8.  Since they demonstrated such utter contempt for their end users in the face of their piracy problems though I shan't be buying theirs any more.  The Prolific ones seem to work fine (though they do also suffer from piracy and the pirated hardware is often less than perfect).

James