Still need to test this out, but I got a new in box “Super Serial Card – Apple Computer”
Details: Apple II serial cards – Wikipedia
Apple Computer’s Super Serial Card, sometimes abbreviated as “SSC”, is the most well known communication card made for the Apple II. Apple called it “Super” because it was able to function as both of Apple’s previous cards, the Apple II Communications Card for modem use and the Apple II Serial Interface Card for printer use. A jumper block was used to configure the card for each of the two modes. The card has a maximum speed of 19,200 bit/s and is compatible with both ROM revisions of the Apple II Serial Interface Card. Reliable communications at 9600 bit/s and higher required disabling of interrupts. The card can actually run at 115,200 bit/s as well, using undocumented register settings; but speeds between 19,200 and 115,200 are not possible using this technique. The Super Serial Card was released in 1981 and utilizes the MOS Technology 6551 ACIA serial communications chip.
Manual: [Wayback] a2_Super_Serial_Card_user’s_manual.pdf via [Wayback/Archive.is] Apple II Super Serial Card – Google Search
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