Byte stuffing question


ETX and DLE should be prefixed with DLE.
What to do if the remote host does not understand such byte stuffing?
Thank you.


Hi Vitaly,

I think that DLE escape sequence is used on the local host (from where it is being sent) to avoid the interpretation of the next control character by the local host.
Normally, if you give an ETX character, the local host would understand that it is the end of connection and would send a TCP segment which would close the connection.
However, if you give DLE followed by ETX, the ETX character would be treated as a data and would be sent across the network which would then be read as it is by the remote host.

Also, much depends on the implementation also. Some of the implementations send the ETX character to the remote host and close the connection. Some don’t.

I would also like other readers on the forum to give their opinion about this as the points that I have outlined is what I understand.
Any suggestion from someone else is most welcomed.

Best Regards,
Open AT Fan.



I think you are talking with the wipSoft (AT+WIP feature) TCP or FTP connection. For this I had already complained that byte stuffing must be implemented with wipSoft’s TCP connection. With old edSoft you can choose to have it or not.

Some applications e.g. virtual serial connection over TCP, cannot handle byte sniffing. Yet Wavecom have not planned changing, very disappointed.