subscribe to our Youtube


14455 questions

17168 answers


0 members

We are migrating to our new platform at Moving forward, you can continue discussions on this new platform. This current platform will be temporarily maintained for reference purposes.
0 votes
363 views 2 comments
by anonymous
Hi, I am trying to collect data remotely from a trimble survey equipment, which has a RS232 connection, using TRB255. I could not get it to work.

I wired TX to 2; RX to 3; CTS to 7; RTS to 8. I wired it like a null modem because they're both DCE.

On the computer side, I used com0com+com2tcp to create a virtual com port and redirect to TCP. I could see the connection in TRB255's realtime data page, but it looks like the command did not go through. I tried HW VSP3 but it seems buggy to me as it gets frozen quite a lot.

The sim card we use has public IP. Is there some sort of settings in the router that could have blocked the serial command?
by anonymous
update: I used putty to verify that it correctly sends serial data. Could be the trimble device's problem.
by anonymous

I got another computer to check the command sent. It seems com0com has an encoding issue. The command sent was œ but on the receiving side it is some other characters

I used eltima virtual serial port driver which has the same issue. HW VSP3 doesn't work at all now. If there is any other software?

1 Answer

0 votes
by anonymous


Could you try connecting the wires like what is shown in this link: 
File:Straight crossed rs232 cable pinout v2.png - Teltonika Networks Wiki (

Regarding the usage of virtual serial port drivers, we don't have data about this. But usually, the connection scheme that we are using is the one found in the link above.