#29 Data corruption

[Oxy]

With the new version 3.0/x64 I can see a strange behaviour: not sure if it happens always or only under some conditions, but when the problem appears, the highest bit of a byte is masked out for some reason. So when sending 0x80 or 0xFF on one side, 0x00 or 0x7F arrives on the other side. This looks a bit like a signed/unsigned conversion problem.

I'm quite sure this is caused by the com0com device because all other parts of the software are left unchanged, only com0com was updated to version 3.0

[Vyacheslav Frolov]

Changes.txt:

• Added cleaning high data bits for less then 8 bit data. For forcing backward compatibility added AllDataBits option.

In other words, if your application uses a 7-bit mask (by default), the version 2 ignores this mask, and version 3 operates in accordance with the standard.

[Alex]

Hello Vyacheslav Frolov ,
I think my app use 7-bit-mask.
I have set AllDataBits =yes, but I have problem to receive fax.
Can you help me?

Many thanks
2020/09/08 00:21:20.015 COM38(e):84c --> 7 bytes of binary
2020/09/08 00:21:24.640 COM38(e):84c --> AT+FTH=3
2020/09/08 00:21:24.640 COM38(e):84c <-- {
0d 0a 43 4f 4e 4e 45 43 54 0d 0a ..CONNECT.. }
2020/09/08 00:21:26.250 COM38(e):84c <-- {
0d 0a 43 4f 4e 4e 45 43 54 0d 0a ..CONNECT.. }
2020/09/08 00:21:26.531 COM38(e):84c <-- {
0d 0a 4f 4b 0d 0a ..OK.. }
2020/09/08 00:21:26.703 COM38(e):84c --> AT+FRH=3
2020/09/08 00:21:31.078 COM38(e):84c Reset state stRecvBegWait
2020/09/08 00:21:31.078 COM38(e):84c COM38 T38Engine ResetModemState
stateModem(5) != stmIdle, reset
2020/09/08 00:21:31.078 COM38(e):84c --> 0 bytes of binary
2020/09/08 00:21:31.078 COM38(e):84c --> ATH0
2020/09/08 00:21:31.078 COM38(e):84c ModemEndPoint::OnMyCallback comm
and=clearcall extra=1
2020/09/08 00:21:31.078 COM38(e):84c ModemConnection::OnReleased Call
[Cbe6777c81]-EP<modem>[modem:201/Cbe6777c81/0]
2020/09/08 00:21:31.078 COM38(e):84c COM38 T38Engine CloseOut: close</modem>

[Oxy]

OK, I found the parameter "alldatabits=NO" below of the COMx-node in Setup. But how can I change this value? Selecting/clicking/double-clickign the item doesn ot work, selection always jumps back to the root node "Virtual Port Pair" of the tree view

[Vyacheslav Frolov]

This option is not implemented in the GUI.
Launch the Setup Command Prompt shortcut and enter the change command, for example:

command> change CNCA0 AllDataBits=yes
command> change CNCB0 AllDataBits=yes

[Oxy]

Works - great, thanks!