Last updated: 14 January 2001

Adding an AUX jack to a 4504 or DS114

From: rseymour@wolfenet.com (richard seymour)

The Meade 4504 (a DS-114 on a German Equatorial Mount, also seen as 114EQ-DH4) comes with a Starfinder version of the Autostar, but no method of connecting it to a PC (no AUX jack to plug in a 506 cable/converter)

I have made a cable harness which simply brought out the 4 wires needed for an AUX jack, plugged a 506 cable set into it... And established communication with my PC. (via Hyperteminal).

I have not run thru much of the LX-200 command set yet... the few i tried -were- understood. And i -could- talk Download protocol to it, and it willingly told my PC that it's version 1.0f and the Autostar type is a binary 07.

And, just for chuckles, i plugged my ETX's focuser into it, and the hold-mode-for-two seconds correctly offered to run it. (and did).

Here's how:

***WARNING*** This puts 12 to 15 volts immediately next to signal lines which will be --destroyed-- if it touches them. Be -very- careful if you build one. Check all wiring twice. Ohmmeter it. The AUX jack is a handset-type jack, which is not carried by RadioShack. www.digikey.com part number H9002-ND or www.jameco.com part number 115128 (both about a dollar) are the -correct- Jacks to use. The Jameco is better, since it has wire leads attached to the jack...the digikey requires soldering.

4504/Starfinder AUX adapter:

Note: in a Starfinder, all of the data lines are the same. They're tied together inside the Starfinder. The Clock (Clk) lines all carry the same -signal-, but are driven by individual driver circuits.

"Az" = RA,  "Alt" = Dec   "A/A"= Alt and Az

Hole in Adapter (to receive Starfinder coil cord)
+-------------------+    1: ground        5: Alt Clk
|  8 7 6 5 4 3 2 1  |    2: A/A Data      6: Aux Data  (A/A in 4504)
|_______     _______|    3: Az Clk        7: Aux Clk
       |_____|           4: A/A Data      8: +15v

Looking at Exposed end of Cable from adapter to 4504 Base
+-------------------+    1: ground       5: Alt Clk
|  1 2 3 4 5 6 7 8  |    2: A/A Data     6: Aux Data (A/A in 4504)
|_______     _______|    3: Az  Clk      7: Aux Clk
       |_____|           4: A/A Data     8: +15v

AUX hole in Adapter      1: Ground
 +-----------+           2: Aux Data (A/A in 4504)
 |  4 3 2 1  |           3: Aux Clk
 +---+   +---+           4: +15v

 HBX    4504    AUX      Signal
 rj45   rj45    rj11 
 Jack   Plug    Jack
  1      1       1       Ground
  2      2               A/A Data
  3      3               Az Clk
  4      4               A/A Data
  5      5               Alt Clk
  6      6       2       Aux Data
  7      7       3       Aux Clk
  8      8       4       +15v  (or +12v or +9v)

 New Starfinder
  HBX jack
  +------+                       rj45 plug
  | rj45 |-----------|<----------> to original 4504 HBX hole
  +--  --+        |
    |__|          |____________+------+  rj11 jack
                               |__  __|  AUX jack for 506 cable
For maximum safety, a fuse and 1 amp diode could be wired in the +15v line, such that current can pass from the 4504 -to- the starfinder and AUX, but not in the reverse direction. It would be in wire 8, in the direction shown by the " -|<- " above.

You can cross-check the pinnage by verifying (with batteries removed) that battery "-" goes to the theoretical "ground" pin, and that battery "+" (the center pin of the power connector, when the switch is "on") goes to the "+15v" pin.

Obviously, the AUX jack could just dangle out of the current Motor hookup box... (but there's very little pin-length available to solder to).

The cable between the two 8-wire connectors (and AUX jack) should be moderately short... i wouldn't recommend over a foot (30cm). Longer wires suffer cross-talk, and confuse the Starfinder.

***WARNING*** this can destroy your Starfinder and/or 506 cable if a wire pops free, or if the 506's AUX plug skews in the AUX jack (say, if you used a normal telephone line jack instead of a handset jack).

more after i've spent some time talking to my new lil' buddy...

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