Serial wotsit ?

[LaVey]

Hi guys...

When I bought the Meade LPI it came with 2 cables, one is a telephone type cable with a small block that fits my hand controller of the scope (has four wires). It also came with a serial converter thingy... I have tried to use this with the Nexstar trial software and ascom celestron drivers.. but it cannot connect to the scope... on closer inspection the cable end of the converter appears to only have 3 pins - and the cable has 4 wires - is this my problem?

Its only £15 for a proper cable to let my lappy talk to the mount via the controller (Celestron NexStar RS-232 Cable (#93920 Alternative) - ML1039 [ML1039] : AstroShop, Astronomical Accessories, Binoculars and Telescopes) so will order one of these anyway. THis is just bugging me :S

[johankj]

Hi,

The cable, or the converter, is probably fine. RS232 (Serial) only uses three wires for duplex: On a 9-pin D-Sub, pin 2 and 3 are RX and TX, and pin 5 is ground.

I haven't gotten around to trying my mount (SW Sunscan AZ) with a planeterium software yet, so I can't help you with that.

If you have XP/W2K you can open up hyperterminal and try to communicate with it, then you'll know it's working. The settings should be in the mount manual, but it's probably 9600 baud, no parity, 1 stop bit, and no flow control. Select the right COM port, which is probably COM1 for inbuildt, and COM(Insert crazy number here) for USB.

You can type in a command and press enter, and the mount should respond accordingly. There should be some example commands in the manual.

Which pins on the 4-pin socket that correspond to which pin onthe DB-9 should also be in the manual, if you think the cable assembly is wrong/faulty.

Hope I'm helping here, and not just confusing...

[LaVey]

excellent info.. many thanks.. will investigate further now I have something to go on

cheers

[Psychobilly]

One of the pins looks like its stuck down on there as well ... The left one... it should be like the two on the right... try and ease it up with a needle...

[johninderby]

The Meade cable won't work with the NexStar, you do need the Celestron cable.

The Celestron cable isn't a straight through cable but has 2 pins crossed over. Pins 2 and 3 will be reversed at the DB-9 connector.

John

[Beyond_Vision]

It's intended for a Meade Autostar #497 Handset it may not be compatible with the Celestron Handset. If the pinout is different you could rewire it to suit.

Regards

Kevin

[LaVey]

ahh.. tried the hyperterminal via com port - no comms..

deffo the wrong cable.

Cheers all

chris

[LaVey]

sorry for double post... gonna have a go at rewiring this cable, so pins 2 and 3, outer pins (1 and 4 physically) of the phone jack, by the pic in my celestron manual, are reversed - so if I split the cable and join 3 to 2 and 2 to 3 that should do it ?

[johninderby]

Have a look at this, it covers the cable wiring very well.

http://www.nexstarsite.com/PCControl/RS232Cable.htm

John

[LaVey]

wohoooo... up and running - excellent resource john - thanks!

OK - so not a biggie - but my first venture into joining wires, and it works and nothing went phizzz! lol

my dual bar came this moring.. so autoguiding test tonight - clouds permitting

edit:

stand by for more questions