Interesting device. I wonder what they were controlling with it. A lot cleaner design internally than some of the older networking gear I have tore down recently.
The serial port controller chips were :MP243EC MAX3243ECPWR 3-V to 5.5-V Multichannel RS-232 Line Driver/Receiver With +/-15kV IEC ESD Protection 28-TSSOP New Original
The Moschip MCS9904CV-AA is a PCIe to quad serial controller.
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https://www.youtube.com/watch?v=ARDHpIh7a4c