Identify component from retro Apple card.

[gmc]

I'm busy reverse engineering a Apple Super Serial Card from the 1981 and come across a component which I haven't been able to find any information on.

Google doesn't find any information on the part and I can only guess looking at the schematic.

Part: 600-0008-A
A 16 pin square block.  The silkscreen on the PCB says modem terminal but I don't think that references the component.

I've attached a picture of  the component as well as the schematic.

The 1488/1488 are quad line drivers/receivers.

My best guess is the component is some kind of inductor/coil to reduce noise, but then am wondering why pin 13 and 14 is connected in parallel if it's just a straight through coil?

It's connected to J1 which then connects to a DB25 connector for serial comms to a Apple II.


Anyone recognise this and know what's it's function is, and what modern day equivalent it can be replaced with.

Unfortunately I'm working from the schematic/photo's so can't do any continuity testing.

[coromonadalix]

i think you could go  with rs323 chip interfaces  since you have 1488 1489  buffers

or any usb rs232 interfaces chip   etc ...  since the 6551  as the tx rx  cts   and other pins

this chip could be some in disguise  since  it is in a big package,  could be a level shifter for the rs232 levels ?

http://www.applelogic.org/files/R6551.pdf
https://mike42.me/blog/2021-07-adding-a-serial-port-to-my-6502-computer
http://jefftranter.blogspot.com/2012/03/6551-acia.html
http://retro.hansotten.nl/6502-sbc/lee-davison-web-site/acia-6551/

[gmc]

Thanks, useful links

As luck would have it just found this in a manual.

It's a simple jumper block.

Now trying to wrap my head around what the connections would be with it connected up and down.

[Andy Watson]

An Apple Parts List:

http://www.bitsavers.org/pdf/apple/service/Apple_Parts_Lists_1984.pdf

page 49, has it listed as "Configuration Block".
My guess would be that it is a block of wire links that can be unplugged and turned through 180 degrees to reconfigure the unit as a modem type of RS232 connection. There's an arrow/triangle on the top that points to either "terminal" or "modem" on the PCB legend.

[gmc]

Thanks. You are spot on. Changing the orientation allows you to connect as a modem or terminal.

[amyk]

Apple's proprietary part numbering scheme has been 3 digits followed by 4 digits for a long time.

[coromonadalix]

Thanks, useful links

As luck would have it just found this in a manual.

It's a simple jumper block.

Now trying to wrap my head around what the connections would be with it connected up and down.

thks  ive been had  loll