ranting on serial I/O cards

[John E. Gefaell]

But that limits you to 2 serial ports, right? Under what conditions and
with what equipment can you use more than 2 serial ports, given that
you are using the other IRQ's on the first controller, like 2 for the mouse
??? Are there dumb serial port cards that can use the second set of IRQ's? 
or can SysV/386 somehow manage sharing interupts? Please lemme know, I've
got a card with two ports, on a 16450 and on a 16550. . . I'd love to get
four ports working with CTS/RTS flow control, etc. . .