06/06/88: TELECOM programs by Delphi, | Category: Delphi - Telecommunications | 11 comments - (Comments are closed)

TELECOM programs

41714 6JUN88-0045 Telecommunications
TELECOM programs

I’m currenly working on a terminal program. If all goes well, I’ll post it
here in DELPHI. I think I understand parity bits, but I’m not sure how to
handle incorrect bytes sent from the other computer. Should I send a NAK
character? Ignore it all together causing it not to echo to the other computer?
Or what. And with XMODEM, I assume that I don’t echo any of the chr$ except
the checksum, right? Or do I just send a ACK chr. I quess I don’t understand
it as well as I thought. Any help will be appreciated.
Ken Halter

11 comments to TELECOM programs

  • pucc_unknown

    41787 9JUN88-0042 Telecommunications
    RE: TELECOM programs (Re: Msg 41714)

    During normal communications, there’s really not much you can do about
    receiving characters with the wrong parity. Some terminals display
    such “munged” characters as question marks. Most terminals and
    communications software just ignores parity, and strips it off
    just prior to displaying it. Thus if you get some “garbage” characters,
    they appear as obviously wrong characters displayed amongst perfectly
    normal looking text.

    Don’t bother to ACK or NAK them, just display them. If you NAK a
    parity error, chances are virtually certain that the computer
    won’t know what you’re talking about.

    I believe we have a file in the databases here, uploaded by MIKEWARD,
    that explains the XMODEM protocol. That would make informative
    reading, judging from your other question. On an XMODEM receive,
    you really do not echo ANYTHING to the screen; you just stuff the
    data portion of each block into the buffer and/or the disk file.
    Each block is preceded by a header that gives some info from which you
    can validate the block, and also has a checksum at the end
    that serves the same purpose. If everything checks out, you can
    keep the yummy data that is “sandwitched” between the data header
    and the checksum. In that case, you send an ACK to the computer,
    to tell it, “That was great, now send more”.

    In the case of an error, of course, you send a NAK to tell the
    computer “Whoops, that don’t look too good; better send that again.”

    There’s more that’s involved, but that’s a quick summary. Take a
    look at Mike’s file for the whole scoop.

  • pucc_unknown

    41820 9JUN88-2336 Telecommunications
    RE: TELECOM programs (Re: Msg 41787)

    Thanks for the help Rick. Since I already have your attention, I assume
    that you’re the same Rick Adams that wrote the game SHANGHI. If so, I was
    wondering if you could give me a hint as to how to patch that game for
    monochrome output. It’s really hard to see with the color burst signal
    enabled. Do you think I might be better off buying a monochrome output for
    my COCO3, like DISTOs. Again, any help is appreciated.
    Thankyou, Ken Halter

  • pucc_unknown

    41829 10JUN88-0046 Telecommunications
    RE: TELECOM programs (Re: Msg 41820)

    Yep, I wrote Shanghai for the Coco3. You will be happy to know that no
    patch is needed for monochrome operation. Just select RGB as the monitor
    type, and the composite output is jimmied to turn on the monochrome bit.
    Sneaky, huh?

  • pucc_unknown

    41867 11JUN88-0236 Telecommunications
    RE: TELECOM programs (Re: Msg 41829)

    Thanks for the tip. I enjoy that game quite a bit. I have to fight the
    ol’ lady for first game.
    Ken Halter

  • pucc_unknown

    41870 11JUN88-0508 Telecommunications
    RE: TELECOM programs (Re: Msg 41829)

    here’s something that should make you impossible to talk to for awhile .

    i just got a chance to play a demo of shanghai on the amiga . and i like the
    cooco version better , mostly for the character set but also the other version
    looks overdone .

  • pucc_unknown

    41888 11JUN88-1101 Telecommunications
    RE: TELECOM programs (Re: Msg 41870)

    Rick, the night I got Shanghai (the same night I got My CoCo 3
    and CM8 monitor) I stayed up until almost 3am playing Shanghai!
    I was determined to whip that dragon. Excellent game! I have seen
    this game on an IBM clone. It was retrieved from some BBS. It looked
    very similar, but had no mouse interface. Ugh!

    ps, Wouldn’t it be nice if Shanghai supported the hires interface
    since it is the main program I run which doesn’t!

  • pucc_unknown

    41894 11JUN88-1132 Telecommunications
    RE: TELECOM programs (Re: Msg 41870)

    The Coco 3 version was originally supposed to look VERY much like the
    Amiga version of Shanghai. At the last moment, Tandy decided they liked
    a different color set for the game, so it looks like it does now. I
    disagreed at the time, but I’ve shown numerous people the old colorset
    (which looks like the Amiga version), and the new one (the one in the
    game as it is now), and most people like Tandy’s choice better. So…
    gee! I guess they really DO know what they’re doing! Pardon
    me while i hush mah mouf!

  • pucc_unknown

    41895 11JUN88-1137 Telecommunications
    RE: TELECOM programs (Re: Msg 41888)

    So did you win the dragon!??

    Hmmmmm, support for the hi-res interface. Why didn’t *I* think of that?
    I wonder if it could be patched in. Hmmmm. (You awake, Don? )
    I know *I* sure hate changing around those joystick cables, TOO.

    Shanghai is a LITTLE difficult to transfer to disk from the Rompak, but
    wouldn’t really slow down any die-hard hackers. But I’m reluctant to
    provide the details myself, due to the many pirates that’d use that info
    in a less-than-ethical manner. Sigh. But ask around, I bet you’ll find
    someone who knows.

    After that, it’s mostly a matter of finding a nice safe place to patch in
    the hi-res interface code, and linking it to the low-res stuff already
    there. Fun.

  • pucc_unknown

    41901 11JUN88-1219 Telecommunications
    RE: TELECOM programs (Re: Msg 41895)

    Patch the hi-res joystick routines into SHANGHAI? I dunno… is there an
    NSA FOOD statement in there?? I only know of ONE wide-open
    message in Shanghai, though…

  • pucc_unknown

    41902 11JUN88-1259 Telecommunications
    RE: TELECOM programs (Re: Msg 41901)

    OH! GOOD POINT, you do point out ONE point in Shanghai where a patch
    area resides. But is it long enuf? I’m inclined to doubt it.

  • pucc_unknown

    41919 11JUN88-2050 Telecommunications
    RE: TELECOM programs (Re: Msg 41902)

    Yes, I have beat the dragon! More than once! Again, great game!
    The hires patch was really just a wish list.

    ps I have the game on disk, the instructions are posted here
    in the forum.