PC control lead for CG5 GOTO.

[Stargazer33]

Hi,

Having just recently received my new scope and mount I was looking at controlling the mount through my laptop via Stellarium.

I see that you need an RJ-45 to RS232 cable and then an RS232 to USB adaptor as most modern laptops don't have an RS232 port on them - nicely kept up with technology mount manufacturers!

If the leads are just straight through adaptors, ie none of the wires change from one pin out to another, can we not use an RJ-45 to USB lead such as this: http://www.amazon.co...45188164&sr=8-2 ? Surely if it is just transferring the signal from the laptop to the mount and vice-versa then I don't see why this shouldn't work.

Does anyone know if the wires are just straight through or is there some special cross-over arrangement that would mean the above cable wouldn't work?

It seems silly putting and extra connection and two extra possible failure points - the connections for the wires to each of the joining connectors - when you could have a single cable with the correct connector on each end!

I could possibly even make the cable up at work after having bought the connectors off of Maplins or RS.

Thanks in advance for your thoughts.

Bryan

[Cornelius Varley]

To control the mount from a pc you need to connect through the handset, not directly to the mount, using a cable such as this one http://www.astronomiser.co.uk/mcc.htm#celestron.

Peter

[Arushin]

Hi,

Having just recently received my new scope and mount I was looking at controlling the mount through my laptop via Stellarium.

I see that you need an RJ-45 to RS232 cable and then an RS232 to USB adaptor as most modern laptops don't have an RS232 port on them - nicely kept up with technology mount manufacturers!

If the leads are just straight through adaptors, ie none of the wires change from one pin out to another, can we not use an RJ-45 to USB lead such as this: http://www.amazon.co...45188164&sr=8-2 ? Surely if it is just transferring the signal from the laptop to the mount and vice-versa then I don't see why this shouldn't work.

Does anyone know if the wires are just straight through or is there some special cross-over arrangement that would mean the above cable wouldn't work?

It seems silly putting and extra connection and two extra possible failure points - the connections for the wires to each of the joining connectors - when you could have a single cable with the correct connector on each end!

I could possibly even make the cable up at work after having bought the connectors off of Maplins or RS.

Thanks in advance for your thoughts.

Bryan

Hi Bryan,

I can't comment on the way these are wired but I have to say that I bought the correct adapter cable from Maplins for under £10 for my NEQ6. It worked first time without any problems and probably cost only a tad more than buying the separate connectors and going through the bother of making it. I've had no problems with it so far. Like you, I think it would be easier if the mount manufacturers would just standardize the connections to USB, but there may well be a valid reason for this not being the case.

[Archaeology53]

Hi,

Initially I had problems connecting a CG5 mount to my Laptop running Stellarium (using a RS232 to USB conversion cable), until I installed a software driver, which came with the conversion cable.

Good luck,

Bill

[TonyM]

Unfortunately, the USB / RS232 adapter is not just a lead - there is some circuitry in there that changes signal levels and protocols between RS232 and USB standards - hence the need for the driver software.

[Stargazer33]

To control the mount from a pc you need to connect through the handset, not directly to the mount, using a cable such as this one http://www.astronomi...c.htm#celestron.

Peter

Hi Peter, sorry I didn't explain things very well. I didn't mean I wanted to connect to the mount directly. I meant plugging into the handset controller and going directly into the laptop rather than the route of handset - RJ-45 - RS232 plug - RS232 socket - USB - laptop!

Arushin, Does your Maplin adaptor go from the handset to the laptop directly or is it adapting from the RS232 plug on the control lead to a USB plug?

Archaeology53, It was the double leads plugged into each other that I wanted to avoid. Looks like I don't have a choice though! Thanks

TonyM, I wondered if it was something like that! I didn't think it would be a straight through connection. Thanks.

[Carbon Brush]

Quote from OP.

I see that you need an RJ-45 to RS232 cable and then an RS232 to USB adaptor as most modern laptops don't have an RS232 port on them - nicely kept up with technology mount manufacturers!

Alternatively, it is nice to see that mount manufacturers have not bowed to the control and computer fashions of the day. Otherwise we would have a plethora of interface standards. Firewire, parallel withall it's variants, IEE488, RS485, modbus, fieldbus, bluetooth, LVDS, USb1, USB2, USB3 to name a few. In fact you could date a mount by it's interface method!

The data transfer between computer and handset (or computer and mount) is small in amount and doesn't have to be there in a microsecond. The low data rates usually used with RS232 help with noise immunity. Fast transients are not seen. Cable runs are generally only a few metres. RS232 is fine for this use up to 10metres or so before other drivers are needed. RS232 also has the benefits of high voltage signalling, further helping noise immunity. The driver components are generally robust enough to tolerate shorts etc. RS232 devices are generally very good at not passing electrostatic discharge back into the computer.

Not forgetting of course the Ascom data standard, another old fashioned idea, that allows you to use any old software with any old mount, within limits. But if this had to work with all the different connection standards, well it wouldn't.

If it ain't broke, don't fix it.

[Arushin]

Hi Peter, sorry I didn't explain things very well. I didn't mean I wanted to connect to the mount directly. I meant plugging into the handset controller and going directly into the laptop rather than the route of handset - RJ-45 - RS232 plug - RS232 socket - USB - laptop!

Arushin, Does your Maplin adaptor go from the handset to the laptop directly or is it adapting from the RS232 plug on the control lead to a USB plug?

Hi Bryan,

Straight from the handset to the laptop. You then need to sync stellarium so that everything points to the same point in the sky.

[Stargazer33]

Just checked my laptop - bought off of e-bay to run my webcams on the scope - and guess what? It's got an RS232 port so lucky old me can just buy the control cable and plug straight in!

Thanks for all the help, sorry I wasted everyones time by not checking first. Obviously the laptop is older than I thought!