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• Pc Serial Pinout
• Laptops With Serial Port Rs232
• Laptop Serial Port Pinout

To connect an LX200 to a computer you need a special cable. You can sometims buy one from the company that makes the software you’re using but it’s much cheaper to make one for yourself. The parts only cost a few dollars and it will take only a few minutes. All you need is a soldering iron, the appropriate connectors and the information below. It’s really a lot simpler that it looks.

Pinouts cables serial. This adapter will enable you to connect a HP48 Calculator at the ) 9 pin computer serial port. 9 PIN D-SUB FEMALE to the Computer. Below is the RS232 connector pinout for testing computer serial port. Data and handshake lines connected. In this case, the sent data is immediately returned back and analyzed by the standard serial port verification software.

Pin-outs

For those of you who know what you’re doing all you need to know is the pinouts:

In the diagrams below the colors indicate which pins connect to each other.

LX200 RS232 Port

At right is a diagram of the LX200’s RS-232 port as you see it looking into the panel. Note the odd pin numbering: 1-4-2-5-3-6, read left to right looking into the port (This numbering is taken from the LX200 User’s Manual, don’t expect to see it elsewhere.)

At left is the corresponding 6-pin modular plug (RJ11) viewed from the flat side (top as it is inserted into the LX200; not the end); the connecting pins are on top, the tab on the bottom of the diagram represents the wire.

Mac Ports

The Macintosh’s modem and printer ports use a DIN-8 jack as shown at right looking into the Mac. The diagram at left shows the pins from the end of the male plug. Of course, it’s a mirror image of the diagram of the port. The pins are usually labeled in tiny raised letters.

Making a Simple Cable

Making a cable is just a matter of wiring up the connectors with matching colors as shown below. Connect pin 3 to pin 3, pin 4 to pin 4, and pin 5 to pin 5. (The exact correspondence of numbers is purely accidental.)

(Crossing lines do not connect)

Making a Dual Cable

Though they are labeled as “Unused” in the LX200 manual pins 2 and 6 are actually an extra RS232 port (pin 4 is a common ground). Thus you can make two simultaneous RS232 connections to your scope. This is useful if, for example, you want to connect to a computer and your CCD camera at the same time.

Connect one connector as above. For the other one, connect pin 6 to pin 3, pin 2 to pin 5, and the common ground pin 4 to pin 4.

(Crossing lines connect only where a dot is shown)

Other Computers

Other computers use a variety of different connectors. Most common are DB-25 (right, top) and DB-9 (bottom); they are shown here looking at the pins from the end of the male connector. Connect as for the Mac substituting per the pin-out table above.

Pin Nomenclature

The various RS232 pins go by a confusing variety of names. Fortunately for this purpose, we need only be concerned with three of them: Ground, RxD (receive data), and TxD (transmit data).

The diagram at right shows how to connect a DIN-8 (top) to a DB-25 (below).

Richard Mathews says, “On the DIN-8, pins 5 and 8 are both Receive Data (actually RxD- and RxD+). The voltage difference between them is what matters. … To reduce noise, you should connect pin 8 to ground by tying it to pin 4. Note that your diagram for connecting a DIN-8 to a DB-25 already shows this connection, but you don’t show it in the info on connecting the RJ-11 to the DIN-8.” Richard is probably right but my cable works fine anyway.

USB

Modern computers have USB instead of serial ports. To use an LX200 with a USB computer you need a cable such as above plus a serial-USB adapter. I use a Keyspan USB Twin Serial Adapter; there are several other similar products available.

Disclaimer

Check your cable carefully before using it. A miswired cable could fry the RS232 ports on either end.

I have made a cable using this information. I have tried to make it correct. But I’m only human. If you burn up your LX200 it’s not my fault.

Notes

• The cable can be very long (100ft or more) if you want. Use heavier gauge wire for longer lengths.
• It can be somewhat difficult to solder wires to the tiny pins on the backs of these connectors. The easy way to make an LX200-computer cable is to buy a cable with an 6-pin modular plug on one end and another cable with the proper connector (DB-9 or whathever) on one end. Then cut both wires in the middle and just solder the wires together. You may have to use a meter to verify which wire is which.
• If you want to avoid splicing wire, special tools for working with modular plugs are available
• You can actually use a 4-pin modular connector if you can’t find a 6-pin one. It will connect to the middle 4 pins of the jack. (But, of course, this won’t work for the dual cable.)
• Though the LX200’s port uses the same connector as your modem it will not work with a modem. Do not use a simple phone cord to connect your LX200 to a modem or to a phone line.
• Pin 1 of the LX200’s port is a 12vDC source. But don’t expect it to deliver much current.
• The LX200’s CCD port is just for moving the scope; it just runs the motors. Some CCD cameras can also use an RS232 port for fuller control of the LX200.
• You can buy all the parts and tools you need from any electronics supply outlet such as DigiKey or Newark.
• For info on LX200 cables see Information about Plugs and Cables by R. A. Greiner.
• Constructing an RS232 cable for a Magellan I by Alistair Symon (Alistair believes this will also work for a Magellan II)
• How to control the LX-200 from a handheld PC by Matt Considine
• Robert B. Denny’s nifty Astronomer’s Control Panel for the Meade LX-200 Telescopes
• Infogenie plugin for Starry Night
• If all this is too much hassle, you can buy ready-to-use cables from Charles Turner

Credits

This page was made possible by the generous contributions of Don Dillinger, Michael Hart and others on the MAPUG mailing list (plus a little help from the LX200 manual, appendix F). I am grateful for their help but any mistakes are mine.

Pc Serial Pinout

Bill Arnett; last updated: 2002 Feb 28

At “Custom pinout” tab you can set custom signal lines pinout, manage signal lines pinout by using pinout presets and create your own pinout presets just in several clicks.

Custom pinout presets:

1. Standard – Default signal lines pinout.
2. Loopback Mode – Enables software think that there is handshaking available, though null-modem does not apply it.
3. Custom – You can select your own pinout of signal lines and save it.

In Standard pinout preset, RS232 null modem scheme with partial handshaking is used:

In Loopback mode pinout preset, RS232 null modem scheme with loop back handshaking is used:

To set custom pinout, please, do the following:

1. Switch to “Custom pinout” tab.
2. Select the required virtual serial pair in the Serial Ports Explorer.
3. Select one of the required signal lines from “IN side of the pair” list for internal serial port and tick the corresponding checkboxes at OUT side.
4. To save settings, enter the desired preset name and click “Save preset” button.

Laptops With Serial Port Rs232

Here is the list of signal lines and their interpretation:

• RTS (Request to Send) – This signal is asserted (logic ‘0’, positive voltage) to prepare the DCE device for accepting transmitted data from the DTE device. Such preparation might include enabling the receive circuits, or setting up the channel direction in half-duplex applications. When the DCE is ready, it acknowledges by asserting Clear to Send.
• DTR (DTE Ready) – This signal is asserted (logic ‘0’, positive voltage) by the DTE device when it wishes to open a communications channel. If the DCE device is a modem, the assertion of DTE Ready prepares the modem to be connected to the telephone circuit, and, once connected, maintains the connection. When DTE Ready is deasserted (logic ‘1’, negative voltage), the modem is switched to “on-hook” to terminate the connection.
• OUT1 – signal is used only by specialized hardware (like the Hayes SmartModem internal board). The meaning of this bit is determined by the hardware using it. For example, if the computer has a Hayes SmartModem board then OUT1=1 resets the modem.
• OUT2 – controls interrupt servicing for the UART: OUT2=0 blocks the interrupt generated by the UART. This allows the user to prevent UART interrupts from reaching the computer’s priority interrupt controller, while still generating them within the UART.
• CTS (Clear to Send) – This signal is asserted (logic ‘0’, positive voltage) by the DCE device to inform the DTE device that transmission may begin. RTS and CTS are commonly used as handshaking signals to moderate the flow of data into the DCE device.
• DSR (DCE Ready) – When originating from a modem, this signal is asserted (logic ‘0’, positive voltage) when the following three conditions are all satisfied:
  • The modem is connected to an active telephone line that is “off-hook”
  • The modem is in data mode, not voice or dialing mode
  • The modem has completed dialing or call setup functions and is generating an answer tone

Laptop Serial Port Pinout

• DCD (Carrier Detect) – This signal is relevant when the DCE device is a modem. It is asserted (logic ‘0’, positive voltage) by the modem when the telephone line is “off-hook”, a connection has been established, and an answer tone is being received from the remote modem. The signal is deasserted when no answer tone is being received, or when the answer tone is of inadequate quality to meet the local modem’s requirements (perhaps due to a noisy channel).
• RI (Ring Indicator) – his signal is relevant when the DCE device is a modem, and is asserted (logic ‘0’, positive voltage) when a ringing signal is being received from the telephone line. The assertion time of this signal will approximately equal the duration of the ring signal, and it will be deasserted between rings or when no ringing is present.
• DTE (Data Terminal Equipment) is a computer or terminal and has a male serial port connector attached.
• DCE (Data Circuit-terminating Equipment) is a modem with female serial port attached.