MPC AP-SIO info?

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MPC AP-SIO info?

I acquired an Apple IIe  enhanced and it came with an MPC AP-SIO card installed. It has a DB-25 connector on the other end of the ribbon cable. It looks like a clone serial card. I can find reference in on-line copies of Byte magazine and google books to the IBM-SIO card and to other MPC cards but not this one. Anyone familiar  with these? Anyone know the dip settings?

 

Thanks.

 

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Another SIO card...

Hi,

I can't help with the MPC SIO card. But I have a very similar question.

I'm also interested in finding out more about my SIO card. This is a card from an Apple IIe and connects the printer (ImageWriter) via a DB25 connector. Two labels on the card say "NPARA-2" (and "N-PARA 2"), but I've been unable to find any documentation on this particular card, nor anything relating to its name. All markings on its ICs were wiped out. I guess it's also some clone/unofficial vendor... 

 

I'd also be grateful for any hints...

 

Thanks...

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Sorry. I don't recognize that

Sorry. I don't recognize that either. Anything on the back?

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It looks like a clone of the

It looks like a clone of the Apple Communications Card.  It uses a 6850 style serial chip instead of the 6551 like used in the Super Serial Card.  It is suitable for printers, but will be a poor performer with modems faster than 300bps.  Even at 1200bps it will swamp the machine with interrupts because there isn't even a one byte send or receive buffer like the 6551 has.

 

 

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softwarejanitor wrote:It

softwarejanitor wrote:
It looks like a clone of the Apple Communications Card.

Thanks. I looked up the Hitachi IC datasheet and figured it was something like that. I guess I'll hold on to it but will keep my eyes out for another serial card.

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softwarejanitor wrote:It

softwarejanitor wrote:

It looks like a clone of the Apple Communications Card. 

There are several cards with a 6850.

 

softwarejanitor wrote:

Even at 1200bps it will swamp the machine with interrupts because there isn't even a one byte send or receive buffer like the 6551 has.

The registers of the 6850 and 6551 are nearly the same. There is one data buffer and the shift register. The difference between these chips is the internal baud rate generator in the 6551 upto 19200Baud and the tricky usage of 115kBaud. The 6850 can run upto 1Mb/sec but has no baud rate generator. There are only some dividers for the external clock. 57600 Baud, 115 and 230kBaud are ok. Over 30years ago my 6850 card ran at 57600Baud, and in the future I will use this chip with 921kBaud. Yes, in an Apple IIe :-)  But no interrupt and no handshake at this speed.

 

Regards

Ralf

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