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Thread: Unknown plug inserted into 5150 cassette port

  1. #1
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    Default Unknown plug inserted into 5150 cassette port

    I bought a 5150 a while back and found this thing plugged into the cassette port. It looks exactly like the connectors on early 5150 keyboards, see here. It just seems to short pins 1&4 and 2&5.
    IMG_2005.jpgIMG_2006.jpgIMG_2007.jpgIMG_2008.jpg

  2. #2
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    From the Cassette port pinout it makes no sense. No sense either from a keyboard standpoint. Doesn't make sense from a MIDI or audio application either.

    There's a fringe audio following that seems to think that shorting plugs by Naim to short unused inputs is a good idea. Perhaps this is one of those.
    Last edited by Chuck(G); January 3rd, 2019 at 12:27 PM.

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    There was also an obscure product (The Desk Organizer) that used the cassette port for a form of copy protection dongle. I have never seen one though so I have no idea if that is one.

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    I don't recall a cassette port dongle, but Fred Collopy, the developer of "The Desk Organizer) has a website, though it looks as if it hasn't been updated since 2009.

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    The July 1983 PC Magazine review spends the first paragraph discussing the dongle with the second paragraph claiming the next version would have an XT friendly form of copy protection. No pictures of the dongle anywhere. Also written in UCSD Pascal, wow, an all in one trivia contest challenge.

    https://books.google.com/books?id=V2...A247&lpg=PA247
    Last edited by krebizfan; January 3rd, 2019 at 01:54 PM.

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    The dongle version of the package must have been very short lived, given that none of the clones had the cassette port.

    But the plug connections don't make any sense for this purpose (see my first post).

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    I think I misnumbered the pins. You can see which ones are shorted in the picture though.

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    I know this is off topic but why has noone in recent years developed some kind of boot strapping program for the 5150 like ADTPro for the apple II. It would be really interesting to utilize the cassette port for modern use since its such an oddity.

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    Quote Originally Posted by VERAULT View Post
    I know this is off topic but why has noone in recent years developed some kind of boot strapping program for the 5150 like ADTPro for the apple II. It would be really interesting to utilize the cassette port for modern use since its such an oddity.
    Well, someone has been researching the cassette port, serial port, and PC BASIC for system booting. All the pieces are there, just need someone to work out useful tools instead of trying it with a Galaxian program. https://github.com/retrohun/blog/tre...ngfromcassette and up the tree is a similar program that boots into Galaxian sent over the serial port.

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    Okay, using the female connector view:



    And looking at the wiring in your 4th picture, we have 1-5, 4-3

    Makes no sense with the cassette plug, but does constitute a "crossover" audio plug:


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