Owner's manual

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APPENDIX D: PERSONAL COMPUTER (PC) CONTROL OF THE #1697 CDS

Remote operation of a computerized telescope has only been a fanciful dream for most amateur

astronomers. The realization of fully controlling a telescope through a personal computer has previously

been a staggering proposition involving high monetary cost and expert knowledge of software and hardware.

To realize this dream, the Meade #1697 Computer Drive System's internal software

supports a RS-232 interface, allowing observers to utilize a PC and software such as

Meade EPOCH 2000sk (see Optional Accessories, page, 18), other after-market

software, or a user's own custom software to control a compatible telescope.

The following sections are devoted to those interested in developing their own

software to remotely control every feature of the CDS.

An RS-232 cable is required for serial communication between the CDS and a PC. It

is possible to either purchase an RS-232 cable from your local Meade dealer, or

construct your own cable. Following is a schematic for constructing your own RS-232 cable, a program to

test the RS-232 communication line called CDS TEST, the CDS Command Set, and CDS DEMO, which is

a program that you can enter into your computer to access the Object Library, slew to the object, and center

the image. The CDS TEST and CDS DEMO programs require a serial communication program, such as

Procomm*, to communicate with a PC.

1. RS-232 Cable

The input hardware uses a standard 6 line telephone jack

connector, preattached to a 6 conductor flat line telephone

style cable (of any length, up to 100' and perhaps even more,

depending on the gauge of the cable). You will also need

either a 9-pin or 25-pin RS-232 connector, whichever your

computer uses for the serial port. All of the above items are

available at most electronics hardware stores.

Fig. 15 shows the CDS pinouts for the 6 line telephone

connector. The table below shows standard IBM compatible

DB-9 and DB-25 serial port pin outs, and how they should be

connected to the CDS 6 line modular connector. Note: Only

3 wires are required.

142 536

Fig. 15: CDS Modular Connector

* Procomm is a product of Datastorm Industries.

** The DB-9 and DB-25 serial port pin out numbering code is representative of a widely used standard format.

Consult your computer’s instruction manual for your computer's format.

RS-232 CONNECTOR PIN OUT CODE LEGEND

6 WIRE MODULAR DESCRIPTION TO DB-9 CONNECTOR TO DB-25

CONNECTOR PIN#** CONNECTOR PIN#**

#1 +12 VOLTS DC NOT USED NOT USED

#2 MISC. SERIAL OUT NOT USED NOT USED

#3 PC TRANSMIT DATA #3 #2

#4 GROUND #5 #7

#5 PC RECEIVE DATA #2 #3

#6 MISC. SERIAL IN NOT USED NOT USED

Fig. 14: EPOCH 2000sk.