TCP Write Problem Sending "FF"

[WKAriyoshi]

Hello people! I'm having a weird problem with TCP Write on sending "FF" (hex). I will explain some tests I have already done and I hope you guys can help me somehow.

My whole system is something like this:

[PC 1] --- [MUX/DMX nº1] --- [RF Transmission] --- [MUX/DMX nº2] --- [Serial/Ethernet Converter] --- [Switch] --- [PC 2]

My objective is to send a message from [PC 2] to [PC 1]. In [PC 2] I use TCP Write and in [PC 1] I use Visa Read.

When I send anything that doesn't contain "FF" from [PC 2], the [PC 1] receives everything correctly. For example, if I send "12345678" from [PC 2], the [PC 1] will receive "12345678".

However, when I send a single "FF", the [PC 1] stops receiving from [PC 2]. Being more accurate, it's [PC 2] that stops to send data. If I send "1234FF5678" from [PC 2], the [PC 1] only receives "1234". Then the [PC 2] stops sending any kind of data and it will only send again if I restart the software. [PC 1] continues to receive data from [PC 2] after this restart. If I send "FF" again, [PC 2] stops once more to send data.

I also tried the other way. [PC 1] used Visa Write and [PC 2] used TCP Read. It worked correctly even sending "FF". I started to think that the problem was in TCP Write.

Then I tried the following scheme: [PC 1] --- [Switch] --- [PC 2]

[PC 1] used TCP Read and [PC 2] used TCP Write. I used LabVIEW's example of TPC Active and Passive and it worked correctly to send "FF". I got more confused.

Then I tried: [PC 1] --- [Serial/Ethernet Converter] --- [Switch] --- [PC 2]

It occurred the same problem as before. [PC 2] sent correctly to [PC 1] every data that didn't contain "FF". When I sent "1234FF5678", [PC 1] only received "1234" and [PC 2] stopped to send data.

Well... now I'm out of ideas of tests. I think the problem is with TCP Write or with my serial/ethernet converter. Do you guys have any sugestion or solution?

Thank you very much. Best regards,

[WKAriyoshi · Accepted solution]

Yahoou! Finally found the problem. The problem was inside serial/ethernet converter. It had an option "Use NVT (RFC2217)". I searched over the internet and found that "FF" for this kind of protocol has a meaning and probably it was affecting my message.

I disabled it and then I was able to send "FF" (hex) without any trouble!

Thanks for your attention. Best regards,