GE Fanuc - connecting the GSM phone

Hi

I have a GE Fanuc Versa Micro UDR0005 PLC. This model has two rs232 and rs485 ports. I want to connect my nokia 6210 phone to it I have rs485->rs232 converter and nokia DLR-3 cable. When phone/plc is connected to the pc the communication via serial port works great but not when both connected with eachother. I know that I need a special cabel for that. Would be grateful if one of you could provide schematics for such cable.

Thank you

Reply to
bartekluk
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You need what is called a "null modem".

Two-wire serial communications take place with transmitted signal on one wire and the received signal on another. Cables are usually made "straight through" with the expectation that transmit and receive pins are reversed on ,say, computer and peripheral. Connecting two computers or two peripherals requires a "crossover" cable or it's equivalent in a box, a null modem.

Jerry

Reply to
Jerry Avins

That's what I thought and I have one cable that was suppose to be a null modem but it is not working and there are few kinds of these. Do you think that cable without handshaking should do?

Reply to
Bartosz

I've no experience with your devices at either end, but it is hard to imagine that the phone interface has enough wires to support hardware handshake. 100% hardware handshake isn't really possible with a null modem: there's no Request To Receive to match RTS.

Jerry

Reply to
Jerry Avins

You need to determine wether your phone is a DTE or a DCE. You can try either configuration in

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would best use an RS-232 tester with split connections.

Reply to
Lanarcam

?? As long as they're both the of the same persuasion, a null modem should allow them to talk. But if each expects the other to talk first, there can be a problem.

Jerry

Reply to
Jerry Avins

Minor nit-pick: Under most implementations of RS232 there is, actually. It's called CTS - Clear to Send. The transmitter sets RTS when there is data in the send buffer, and the receiver sets CTS when it it ready to receive.

Most null modems also connect DSR to DTR - a similar handshake, only an "older" version not much used any more.

Cameron:-)

Reply to
Cameron Dorrough

There are several varieties of null modem, depending on whether you have a DTE-DTE or DTE-DCE connection and also on connectors pinout. An RS-232C tester allows you to see signals through LEDs and change the connections with jumpers, very neat;)

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Reply to
Lanarcam

My cable is a standard 9 pin and the links to the cables provided are for a cable that has at least 20 pins. Do you know what kind of connection do I need to connecy nokia with fanuc? I don't have access to any serial port tester.

Reply to
Bartosz

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I assume without direct knowledge that the serial interface for a telephone needs only Tx, Rx, and Gnd. What does the connector look like?

Jerry

Reply to
Jerry Avins

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shows two simple RS-232 testers. You've already spent more time than one is worth. Some slightly more elaborate ones come with jumpers or switches to cross certain wires.
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?Menu=/English/Content/Categories/CatM_69.asp%26Detail=/English/Content/Items/XC-138.asp shows something like that. Cheap enough for most jobs.

Jerry

Reply to
Jerry Avins

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