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connect CELL215 with COM4 of CR1000

Chasper B. Jan 15, 2020 07:02 AM

Hi there

I set up a system with a CR1000 and a CELL215. With a CS I/O-connection between the devices I finally got the system running, but actually I want to use a RS232-connection to be able to power off the modem completely. And as I want to use the RS232-connector on the logger for the connection to my PC, I would prefer to use the COM4.

Does someone know if this is possible and how I should connect the modems socket to the loggers ports?

As I read in the CELL215-manual I should use a null modem-cable. I put a cable like discribed here, under no handshaking: https://en.wikipedia.org/wiki/Null_modem and installed a diode in the loggers Rx-line, to prevent the logger from negative signals. Actually, with this set up I couldn't establish a connection between the modem and the logger.

Thanks a lot for your help and best Regards,


Chasper B. Jan 15, 2020 11:10 AM

I found a useful hint on the CELL215-product page, where the pig-tail cable https://www.campbellsci.com/p17855 is described for my purpose. As I wired my connection as DTE (DE9-pin2 to Rx, DE9-pin3 to Tx) it works fine.

In my understanding this is a strait connection and therefore no need for a null modem-connection between the CELL215 and the CR1000 or do I missunderstand something?

What about the negative signal on the loggers Rx-port, is there no danger of damaging the port with the negative part of the RS232 signal? Or would it still be better to insert the diode?

Thanks a lot in advance for clarifing my missunderstanding of RS232. ;-)

Best Regards,


JDavis Jan 15, 2020 01:27 PM

The zener diode is built into later revisions of the CR1000. I can't remember the serial number break. Regardless, the CR1000 would not suffer any harm. The consequence on old hardware is false counts on P channels.

Chasper B. Feb 11, 2020 03:34 AM

Dear JDavis

Belated, thank's a lot for your advise. The diode I had in mind from a former installation, was for the ring signal of a modem. I only had a bit confusion about it.

Now everything's running well.

Thank you and best Regards,


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