B&B Electronics 232CC1B, 232CC2B, 232CC2A, 232CC1A manual Interrupt Jumper Setup

Table 3. Frequently Unused Port Addresses

Base	Binary	Switch	I/O Space
Hex	Equivalent	Settings	Description
Address		MSB LSB
		7654321
200	1000000000	1000000	game port
208	1000001000	1000001	game port
300	1100000000	1100000	prototype
308	1100001000	1100001	prototype
310	1100010000	1100010	prototype
318	1100011000	1100011	prototype
380	1110000000	1110000	SDLC
388	1110001000	1110001	SDLC
3A0	1110100000	1110100	bisync com
3A8	1110101000	1110101	bisync com

Interrupt Jumper Setup

The IRQ is a hardware Interrupt Request line in an ISA Bus expansion slot on a PC or AT compatible computer. The 8 bit PC ISA slot has 8 interrupts, the 16 bit slot has another 7 since one of the first 8 is used to link in the remaining 8. The IRQ is used by devices to request immediate service by the main microprocessor. When the IRQ line is set, the microprocessor stops whatever it’s doing, saves status, checks which line was set, then jumps to code to handle the interrupt. The processor then clears the interrupt and returns to what it was doing before. IRQ lines are set by the internal timer, keyboard, hard drive controller, PCI, USB controller, sound card, serial ports, printer and more.

The 232CC cards allow the use of interrupts (IRQ) 2, 3, 4, 5, 6, 7, 10, 11, 12, 14, and 15. Table 4 shows the standard serial port IRQ settings. NOTE: If two ports use the same IRQ setting, both ports cannot use the serial port at once. Only one port at a time may communicate.

Table 4. Standard IRQ Settings

COM1	IRQ4
COM2	IRQ3
COM3	IRQ4
COM4	IRQ3

34 Documentation Number 232CCxx4502

B&B Electronics Mfg Co – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax 815-433-5104 B&B Electronics Ltd – Westlink Comm. Pk – Oranmore, Galway, Ireland – Ph +353 91-792444 – Fax +353 91-792445