Meade Instruments 1697 Computer Drive System For LXD 650 and LXD 750 Mounts - Part 2 - Manual (Page 17)

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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
6
3
5 4 2
1
Fig. 14: EPOCH 2000sk.