this ISA card is not what it seems! 🧵
oh, but it's just a SCSI card with onboard cache SIMMs and an activity LED, you say.
does this look like a SCSI connector to you? it's got 78 pins.
these aren't RAM chips on the SIMMs.
and these aren't chips you'd find in any SCSI card. these are dual UART chips. yes, this board has eight serial ports.
they're not RS232, they're RS485. it uses differential signaling so it can be transmitted over longer distances, and it's multi-drop so multiple devices can share the same wires.
🇨🇦
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