B&B Electronics 3PXCC4A manual Address and IRQ Setting Address Switch Setup

Chapter 4: Address and IRQ Setting

Address Switch Setup

A Windows PC has I/O port addresses and memory addresses. Some devices use both types of addresses. I/O port addresses have a 64K address space. Devices may decode all 16 address bits or only some of the lower bits. Traditionally, serial cards have only decoded 10 bits of the address bus. Recently this has begun to cause address conflicts with full 16 bit decoded devices, most notably between video cards and COM 4. B&B has solved these conflicts by decoding all 16 bits of the ISA address bus. Address settings in our ISA bus serial cards is set by DIP switches (selecting bits 11-4) or jumpers.

CAUTION: Electrostatic Sensitive Device.

Use ESD precautions for safe handling.

B&B Electronics 3PXCC4A cards are factory configured for COM1 (IRQ4), COM2 (IRQ3), COM3 (IRQ5), and COM4 (IRQ7). If you plan on installing two of the four ports on the 3PXCC4A as standard COM1 and COM2, you may leave the address and IRQ set to the factory defaults for COM1 and COM2.

The 3PXCC4A cards use a 7-position DIP switch to program the binary I/O address of each port on the card. Figure 1 is a drawing of the printed circuit board that shows the locations of the setup switches and jumpers on the 3PXCC4A cards.

Manual Document# 3PXCC4A3001 31

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