Last updated: 12 November 2000

Autostar Cable Info

From: Cameron Brennan (etx@neurosurgeon.net)

Thank you for your wonderful site. It was a strong influence for my purchasing an ETX 90/EC as a first scope. _________________________________________________________________________________

I have determined a candidate pinout for the RS232 port on the ETX Autostar. The Autostar appears to emulate LX200 commands, and I have been able to drive the scope directly from HyperTerminal as well as from the Sky Map software package (which I recommend for starters).

The caveat is: this pinout was found by trial-and-inference; it is unofficial and appears unsupported by Meade at this time. If you are not willing to risk frying your Autostar, don't try it! I also am not an expert in RS232 protocol, so although I can tell you what worked for me, there is every chance it is sub-optimal.

Pick up the Autostar with the display facing upwards. Looking into the 4-pin RS232 port, the pins can be numbered, L to R, as 1 to 4 respectively: (best viewed in fixed-width font)

(4-pin RS232)   (8-pin to ETX)
    ___              ___
 __|   |__      ____|   |____
|         |    |.............|
|         |    |.............|
|_1 2 3 4_|    |_____________|

pin 1:  Autostar Receive
pin 2:  Autostar Transmit
pin 3:  [ground? appears to be connected directly to pin 4, but I leave
it alone]
pin 4:  ground

I have made a simple cable to connect to my PC-compatible laptop serial

Autostar pin:             Serial port pin:
#1........................#3 (PC Transmit)
#2........................#2 (PC Receive)
#3........................ no connect
#4........................#5 (ground)

The 4-pin jack is NOT the same size as a standard telephone RJ11/14 plug. I had to file a plug down to get it to fit. Mind that an ill-fitting plug does not get stuck in the Autostar.

It has been written of the LX200 that the scope must be aligned prior to initiating control commands, and this appears to be the case for the ETX.

HyperTerminal manages to communicate with the following settings, although others might work or might be more appropriate for flow control:
 Baud: 9600
 Data: 8
 Parity: N
 Stop: 1
 Flow Control: None

The LX200 Command Set can be found on the web.

The "Clone" function does not dump directly to HyperTerminal with these settings. It will hang the Autostar until the ETX is turned off.

May your Autostar survive, and Happy Slewing!


Mike here: Use this tip with caution. You will probably invalidate your ETX warranty. Any damage caused by following this tip is not the responsibility of the contributor, myself, nor America Online.

Subject:	 ETX/EC Pinout
Sent:	Wednesday, February 10, 1999 5:34:08
From:	Dick Walters (dick@dwalters.com)
The 4 pin plug is  std 4-pin "handset" plug, which has the same pin
spacing as the RJ-11. I believe this is the RJ-22.These things are
pretty rare at Radio Shack, probably to keep folks from going home with
the wrong plug. You can find them at some electronics supply houses. Big
problem is that some crimp tools won't work.  Only one I've found is the
Paladin 1530, a rather pricey tool.

Dick Walters
Subject: Autostar Serial Cable addendum Sent: Monday, April 5, 1999 10:29:42 From: Watkins.Reece@bis.bls.com (Reece Watkins) I successfully made the RS-232 cable for the Autostar as per the instructions on this site. I just thought I'd pass along some additional info that I discovered while constructing mine. Radio Shack sells a 25' handset cord that is nearly the color of the ETX tube. It is part# 279-286 and the color is listed as "Blue", although it looks more purple to me. USD$7.99 If you're going to use the crimp-type 9-pin connector listed in Dr. Triola's part list, make sure you get a crimp pin insertion/extraction tool as well. I've forgotten the part number, but it's in the vicinity of the hood and connector on the parts wall. It's a two-piece red and white tool about 3 inches long with metallic pushers extending past the ends. USD$2.99. Unnecessary if you use a solder-type 9-pin connector, but VERY useful for the crimp-type connector. To help with strain-relief, before you place the connector in the metal hood, tie an overhand knot in the handset cord as close as you can to the connector. Make sure the knot fits inside the hood ahead of the clamp jaws. This way, if the cord gets pulled hard, it will tighten the knot and pull it against the clamp jaws instead of yanking those small wires out of your crimp pins. Since the rubber jacket on the coiled cord is springy, this may be a tight fit inside the hood, so be patient in getting it all in there. But trust me on this one. You may wish to clip wires 2, 3, and 4 a little shorter than wire 1, as wire 1 has to be a little longer to make the crossover into pin hole #3 correctly. Make sure wire 3 isn't touching anything, but don't clip it all the way back as there may be a use for it we don't know yet. Don't strip the end. Save your extra crimp pins ( you get about 11 in the package.) Radio Shack's handset cords' wires are NOT color-coded. (well, mine weren't, anyway) If you do not have a multimeter/continuity tester, pick up a little 1.5-volt wired lightbulb (USD$1.19) when you get your parts, and MAKE SURE you are wiring the right wire to the right pin. Remember, Cameron's diagram is for the Autostar SOCKET, and orient your thinking accordingly, i.e., remember to test the plug with the gold pins facing the floor instead of the ceiling when you are numbering your wires. The cable is very easy to make, even if you aren't handy with a soldering iron. It took me all of about 15 minutes, most of which was double checking the continuity of the wires with my little light bulb. The trickiest parts were stripping the little wires and getting the strain-relief knot into the hood, but that's just manual dexterity. I completely assembled mine in my lap on the couch watching TV last night with just a pair of wirecutters, a screwdriver, and a pair of needlenose pliers to crimp the pins onto the wires. SkyChart III 3.1 (www.southernstars.com) works OK with the cable, if you choose the LX200 mode. However, I could not get it to send commands to the ETX--rather, it would display the RA and Dec of the scope and update the screen to show where the ETX was supposed to be pointed. I believe it may have something to do with how my COM port was configured, I believe I had it set to Hardware flow control, which obviously this cable isn't set up for, now that I think about it. Haven't tried SkyMap 5 yet. I didn't have a lot of time to play with it last night, but it sure looks promising. Standard disclaimers apply, hope this helps other electronically-challenged people like myself! Reece Watkins

Added later:

I've confirmed that SkyChart III 3.1 is only read-compatible with the
Autostar.  It can read the Autostar's coordinates just fine and plot the
scope's position on the chart screen, but cannot send the right commands
back to the telescope to slew it remotely.  You must slew and/or GoTo
with the handbox.  It appears that SkyMap Pro 5 Demo/Full is the only
software that will correctly operate the Autostar at this time.

Subject:	 Simple autostar cable solution.
Sent:	Monday, May 17, 1999 11:47:58
From:	warren@pcis.net (Walter Warren)
Here's an easier way to make a cable to connect the Autostar to a
computer that requires only a screwdriver with no cutting nor soldering.
My solution is a standard unmodified handset cord with an adapter to
connect it to the computer's serial port. Cost was $2.99 + tax and took
about 5 minutes after acquiring the parts.

I saw a part in a Data Comm Warehouse catalog (www.warehouse.com) for
$6.99 that was a DB9 (female) to RJ12 adapter (part number 0373-3).  The
price was $6.99 but S/H was expensive. After a couple of calls to local
electronic parts stores I found one for $2.99.  Sorry, I don't have a
part number, the pieces just came in a small zip-loc baggie. There were
4 pieces (2 halves of a plastic shell, a DB9 female connector, and a
RJ12 jack.) and assembly screws. Wires were already attached to the RJ12
end with the DB9 "pins" attached at the other end.  I simply snapped the
pins into the appropriate holes on the DB9 connector (as detailed
elsewhere by others) and screwed the two halves of the adapter together
to complete the job.  IMPORTANT: The RJ12 is 6 wire instead of 4.  You
have to ignore the outermost wire on each side and only consider the
inner 4 wires. I clipped off the extra 2 wires to avoid confusion and
conserve space inside the shell. Also, because the handset cord you'll
be using is wired straight through, the RJ12 pins will be numbered
reverse of the autostar pins. The leftmost pin on the autostar
corresponds to the rightmost pin (again, ignoring the extra pins) of the
adapter's RJ12.  If your computer serial port uses a 25 pin connector
instead of 9 pin, there is also an adapter available for that.  I don't
know if the pin configuration will be the same.

As for the cable itself:  The RJ12 jack is the same size as a standard
RJ11 telephone plug, which of course is a little bigger than a handset
plug.  A handset plug fits perfectly in the Autostar. In the adapter, a
handset plug fits securely, but sits a little cockeyed in the larger
hole.  With the adapter assembled you just plug a standard handset cord
into the adapter and the autostar.  There's no need to buy a special
handset cord.  For occasional use, just unplug one from a standard phone
you already have.

Walter Warren

Subject:	Homemade Autostar Cable
Sent:	Monday, May 31, 1999 23:36:14
From:	LooneyRoo@aol.com
well, i fiddled with the damn cord for about 4 hours before i noticed
that i had the entire setup all backwards!! the diagram on your site
shows the connection as it would be if you were looking inside of the
autostar port... i did not take into account for the fact that it would
be completely opposite on the cable... i think you tried to explain that
to me when you told me to switch the 2nd and 3rd cable, but i just
didn't understand.... but now i got it!!. it took about 30 minutes to
upload the software and i did a rough polar alignment outside and had
great results with the 1.1m... so thank you for your help and for those
who contributed to the site!!!


p.s. - for those out there who are leery about making your own cable
because you are afraid of frying your equipment... don't worry, because
i tried every pin combination and my scope and autostar are still
ticking!!! (not that this is in any way a guarantee from meade, mike or
myself) -- but if you follow the directions posted on the site, you
should be fine.
Added later:
i have what will hopefully be my final "autostar update" question... as
i said in my last post, i successfully downloaded version 1.1m and it
worked perfectly. my next adventure has been to upload the other two
elements that the meade download page is offering (comets and bright
minor planets)... i have downloaded these two files in the "text only"
format, but when i open my "autostar update" program, the only option is
to upload version 1.1m... there are other spaces available, but they
seem to be unavailable. i'm sure that the files were copied to the
autostar update program, so that's not it. hopefully you can give me an
idea as to what the problem is. thanks again!

Subject:	 Auto Star Uplink cable
Sent:	Tuesday, June 1, 1999 21:37:28
From:	don.phipps@juno.com (Donald L Phipps)
I came up with another inexpensive "homebrew" cable, using a telephone
handset cord with one connector removed,  3 small wire pins, and the
left over PC connector to Serial connector from a new mouse.  I followed
the pin-out schematic described by Cameron Brennan, after identifying
the pin-out for the adapter.

The assembly process was about 10 minutes, and it worked the first time
I tried it.  I had an electronic formated drawing of the setup, but the
system crashed before I could save it.  I will re-do the drawing and
description of each piece later this week if possible and send it to you
via e-mail, so that you may share it with others.  Total cost to me was
$4.80 for the cord and 25 minutes total time identifying the pin--out
and soldering the pins to the wires.

This is much easier than trying to locate the RS-232 to 4 wire Rj-12 or
14 jack. adapter.

Happy sky watching!

Don Phipps
Thou wilt keep him in perfect peace            
whose mind is stayed on Thee,                    
because he trusteth in thee.

Subject:	 AutoStar cable Using PC Mouse Serial Port adapter
Sent:	Wednesday, June 2, 1999 7:47:11
From:	Donald.Phipps@kp.org (Donald Phipps)
I have had my ETX since Jan 1, 99 and love using it quite often.  I
purchased the Autostar two weeks ago, and wanted to be able to update it
by uploading the files from the internet to my PC and then to the
Autostar.  The cable setup illustrated below, took about 20 minutes to
put together (verifying the pin-out and creating the wire pins to plug
into the mouse serial connector.  When completed, the pins were
insulated with electrical tape, and a protective boot of black
electrical tape finished the connector.  The complete setup cost less
than $5 to build from components in my "Ham junk box".

Here is a drawing.  It is fairly simplistic, but I trust it will be
helpful to some.


Donald L. Phipps     -- ARS: KH6LO

Subject:	 Autostar Cable Info update
Sent:	Tuesday, June 22, 1999 18:27:14
From:	cburton@evolving.com (Charles E. Burton)
Cameron Brennan's (etx@neurosurgeon.net), Brian Nakata's
(bnakata@cybcon.com), Reese Watkins (Watkins.Reece@bis.bls.com), and Dr.
Marc Triola's (mtriola@ibm.net) instructions on building a cable from
the computer to the Autostar was very helpful.  I have a few of updates
that I would like to make.

First, let me point out that I am an electrical engineer and have had
much experience in building computer cables.  Generally, cable
connections come in pairs (signal and return/ground).  The signal wires
are usually wrapped (either shielded with a ground sheath, like a coax
cable, or are twisted with the ground wire).  These configurations help
reduce noise pickup by the signal wires.  However, that is not true of
ribbon cables, like the telephone cables (RJ11 and RJ12) that are
discussed in many of the articles.  If you cut open the Radio Shack
handset cable, you will find a red, a black, and two white wires.  I
would suspect that the red and black wires are for audio signal in and
audio signal out and that the two white wires are used as the
return/ground wires.  The red and black wires are attached to pins #4
and #1, respectively, being separated by the two white (ground wires). 
The separation by the ground wires is to reduce crosstalk between the
incoming and outgoing signals.  Now to the Autostar pinouts, since #4 is
connected to ground and because the impedance difference between #4 and
#3 is very, very low (almost 0 ohms), it is my opinion that pins #3 and
#4 should be tied together and connected to DB9 #5, because they are the
return/ground wires for the two signal wires (#1 and #2).  However, the
way it has been suggested to wire the DB9 will work since the ground
return for both #1 and #2 will be done by #4. For the digital signals
that move over #1 and #2, isolation of the signal returns/grounds is not
important, so you can wire it either way and everything will work.

My second point has to do with a DB25 connector, rather than a DB9.  My
connection had to be done with a DB25 connector, and I assume others
will have the same problem.  I could have wired things up as suggested,
but would have to add a DB9F-to-DB25F adapter.  Instead, I chose to
directly wire to a DB25 male connector instead.  For those of you that
need a DB25 connector, instead of a DB9 connector, I offer the following
(using Cameron's drawings):

          Autostar base
(4-pin RS232)   (8-pin to ETX)
    ___              ___
 __|   |__      ____|   |____
|         |    |.............|
|         |    |.............|
|_1 2 3 4_|    |_____________|

pin 1:  Autostar Receive
pin 2:  Autostar Transmit
pin 3:  ground
pin 4:  ground

Autostar                DB9 Serial              DB25 Serial
pin:                    port pin:               port pin:
#1....(PC Transmit)......#3......................#2
#2....(PC Receive).......#2......................#3

Thus, we see that the DB25 transmit and receive pins are reversed from
the DB9 layout and that pin 7 is the ground pin, instead of pin 5.

Finally, since the cloning cable attaches between two Autostars, you
need a handset null modem cable (swaps signal and ground pairs):

Autostar 1              Autostar 2
pin:                    pin:

To build the null modem cable, you can use a handset cable, cut off one
connector, and crimp on a new handset plug (after reversing the
appropriate wires).  I would expect Radio Shack to have all of the
needed parts.  Don't mix up #2 and #3 (the white wires), because you
might burn out the Autostar transmitter on one of the Autostars.  Either
end of the cable can be plugged into either Autostar.  The cable wiring
takes care of the magic.

Disclaimer: Use these suggestions at your own risk.  Any damage caused
by following these tips is not my responsibility or that of my ISP or my
employer or anyone else, for that matter.  You take responsibility for
you own actions.

Happy downloading,
Chuck Burton

P.S.  Thanks for the great ETX site, Mike.

Subject:	 Autostar Information ...
Sent:	Thursday, November 9, 2000 08:55:57
From:	jon.swarner@gtri.gatech.edu (Jon Swarner)
I am writing this to add to Walter Warren's post concerning the control
cable for the Autostar.  I also found the part that he used at a local
retailer in Atlanta, ACK Electronics.  They also do mail orders.  They
have two locations; Atlanta (800) 282-7954, and Birmingham (800)
338-4218.  They also have a website at www.acksupply.com.  The part
number for the adapter is: 40-9526F AIM.  It costs $2.97.  To overcome
the wobbly plug from the handset cord, I also got a 6 pin RJ-12 plug
(part number 30-9915 GC; $0.69). I was able to "crimp" it using a
jewler's screwdriver to press the pins in, eliminating the need for an
expensive crimping tool.  To use the Adapter from Ack, simply connect
the yellow wire in the adapter to pin 3, the green wire to pin 2, and
the black wire to pin 5.  You can cut the red, blue and white wires if
desired for more room.  The whole assembly (adapter and cable) took
about 5 minutes, including determining the pin-out.  I am using it with
Skymap Pro version 7 (demo) and it works like a charm!

Thank you for the great site!

Jonathan Swarner

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