Re: Serial port redirection

Jeffrey Altman
2003-12-03T16:36:17Z

[-- Attachment #1: Type: text/plain, Size: 3287 bytes --]

Its not a Kermit bug; If you pass the socket file descriptor to an
external program
the external program must understand telnet protocol. Otherwise, it
can't send the
correct data format.

Peter Astrand wrote:

>>Hi. I'm trying to find a generic serial port redirection solution for a
>>Linux terminal server environment. I'd like a solution based on RFC2217.
>>I'm particularly interested in syncing Palm Pilot PDAs.
>>
>>
>...
>
>
>>ser2net/sredird + Kermit
>>------------------------
>>Kermit has built-in RFC2217 support, but it doesn't work for me:
>>
>>---
>>C-Kermit>set host localhost:4911
>> DNS Lookup... Trying 127.0.0.1... Reverse DNS Lookup... (OK)
>> localhost.localdomain connected on port 4911
>>C-Kermit>set speed 2400
>>localhost.localdomain:4911, 2400 bps
>>C-Kermit>connect
>>Connecting to host localhost.localdomain:4911
>> Escape character: Ctrl-\ (ASCII 28, FS): enabled
>>Type the escape character followed by C to get back,
>>or followed by ? to see other options.
>>----------------------------------------------------
>>,
>>Communications disconnect
>>---
>>
>>
>
>Well, this was my fault: I didn't understand how Kermit worked. When using
>"set carrier-watch off", things worked much better.
>
>* BUT: When using Kermit as a RFC2217 client for transferring files with
>ZMODEM, I get "Bad CRC" pretty much all the time. This happens *both* with
>the sredird, ser2net and Tactical Softwares Dialout/Server for Windows.
>The problem seems to go away if I transfer files without "0xff" bytes(!)
>This looks like a Kermit bug to me. I'll guess I have to talk to the
>Kermit folks about this.
>
>
>* ser2net is totally incompatible with cyclades-serial-client. This is
>because ser2net interprets RFC2217 a bit differently. sredird sends
>command "101" as ack for command "1", while ser2net sends "1". RFC2217 is
>not very explicit about which way is most correct. The ser2net approach
>looks better to me, but the sredird one is probably more widely used
>(since Cyclades terminal server uses it, for example.) Probably, RFC2217
>software needs to handle both cases.
>
>
>Some more test cases:
>
>* minicom + cyclades-serial-client + sredird:
> Works
>
>* pilot-link + cyclades-serial-client + sredird:
> Does not work (see my previous mail)
>
>* pilot-link + cyclades-serial-client + Dialout/Server:
> Works perfectly.
>
>* photopc + cyclades-serial-client + sredird:
> Does not work. I get "excessive retries".
>
>* photopc + cyclades-serial-client + Dialout/Server:
> Works perfectly.
>
>So, the combination of sredird + cyclades-serial-client does not work
>correctly.
>
>Also, I tried running "Contract I.T. Communications Analyzer" on a Windows
>machine. One physical port was connected to a Linux machine via a null
>modem cable. This machine ran sredird. One virtual port was created with
>Tactical Softwares Dialout software, connecting to sredird. Communications
>Analyzer indicated 90% Byte Error Rate! Since cyclades-serial-client was
>not involved in this test, I would say that it looks like sredird is doing
>something wrong.
>
>
>If *anyone* has any ideas of how to solve these problem, please let me
>know. I'm starting to run out of time and patience...
>
>
>(Which mailing list is best for this topic?)
>
>
>

[-- Attachment #2: S/MIME Cryptographic Signature --]
[-- Type: application/x-pkcs7-signature, Size: 3427 bytes --]