HM6666ALP, Model 6666, HMC666A, 8905C

ISA Controller Card with Game Port, 2 Parallel Ports and 2 Serial Ports

(Click here to get a larger view)

It is awfully hard finding information on this card on the internet. So I tried messing a bit with it myself. These are the results:

• Port	I/O	IRQ
  COM1	3F8	Set by J3
  COM2	2F8	Set by J4
  COM3	3E8	Set by J3
  COM4	2E8	Set by J4
  LP1	378	7
  LP2	278	5

• My testing program reports that the second parallel port (LP2 - the one you have to connect yourself) has an inverted IRQ logic. Depending on your application you might not be able to use it.
• J3 and J4 are for setting the IRQ of the serial ports. J3 sets the IRQ for COM1 and COM3, J4 sets the IRQ for COM2 and COM4
  Defaults: COM1: IRQ4, COM2: IRQ3
• I haven't yet found out what JP5 is for. I believe it is for enabling the Game Port. Concering my other results, I guess it really is for DISABLING the game port. If someone of you has more information about this - drop me a line!
• The Jumpers between the texts J1 and P2 are for disabling COM3 and COM4. Funny thing: There are only two connectors on the board, so COM3 is the same as COM1 and COM4 is the same as COM2. They still have different hardware addresses.
  With those jumpers it is possible to have 4 Ports in your system. Although I can't think of any reason for this I can guess there are applications.
  More interesting is it to only have COM3 and COM4 on this card, in case you already have COM1 and COM2 on another controller
  Note that the Ports are DISABLED, when you put jumpers over those connectors.
  The left Jumper disables COM4, the right Jumper disables COM3
• SW1 has four connectors. I read them from left to right (SW1.1 is the leftmost)
  You can disable LP2 (I/O 278) by setting Jumper SW1.1
  You can disable COM2 (I/O 2F8) by setting Jumper SW1.2
  You can disable LP1 (I/O 378) by setting Jumper SW1.3
  You can disable COM1 (I/O 3F8) by setting Jumper SW1.4
• So in order to have the most connectors enabled, you simply remove all the jumpers (except IRQ-Jumpers J3 and J4). (not sure about Gameport) That way you also have a "virtual" COM3 routed to COM1 and a "virtual" COM4 routed to COM2.
• In order to have 2 serial and 2 parallel connectors, remove all jumpers from SW1 but set the two next to J1.
• If you already have 2 serial ports and 1 parallel port, remove the Jumpers next to J1, but set SW1.2, SW1.3 and SW1.4. That way this card gives you LP2 and COM3 and COM4
• The serial ports are 16450 - not the fastest ones
• The parallel ports are 4-Bit