[Info-vax] yet another sys$qiow question

[Johnny Billquist]

On 2015-08-12 00:38, kc at kayceesoftware.com wrote:
> this is slightly related issue only as it pertains to the same serial comm to a card reader.
> to refresh: vms 8.4 IA64, tcpip 5.7 ECO 5, C 7.3-018
> sys$qiow working fine now and seems very stable, my problem was getting the terminator mask correct.
>
> I've been reading on sockets and will be converting to that mode soon for another project and probably change this serial code at that point.
>
> BUT, in researching a very random NAK of my comm, i've found that the CRC sometimes calcs a line feed (LF, ox0a), and the stored string shows ONLY the LF i put in it....but the message that ends up at the card reader has CRLF, which is then rejected as invalid.
>
> The terminal port (TNA1) is set pasthru, the VMS IO Ref Manual says IO$M_NOFORMAT and TT2$M_PASTHRU are basically the same.
>
> So, is it the TT driver, or tcp, or something else converting the LF to CRLF?

While I cannot answer, I should repeat what I pointed out before. The 
"telnet" protocol is really just a TCP stream, with a couple of things 
thrown in. 0xff is special, and you are expected to use the network 
virtual terminal convention/protocol. One thing with that is about how 
to deal with CR and LF. And depending on various parameters and 
configurations, this could throw a wrench in your communication.

Running tcpdump and capture the traffic would be the easiest way to 
confirm if the data transmitted contains a CR, or if the receiving end 
adds it.

After that, you might want to continue hunting in greater depth wherever 
the trail leads you...

	Johnny

-- 
Johnny Billquist                  || "I'm on a bus
                                   ||  on a psychedelic trip
email: bqt at softjar.se             ||  Reading murder books
pdp is alive!                     ||  tryin' to stay hip" - B. Idol