Lucent Technologies 560-201-113 manual

PC Serial Ports

Given the scenario described in item (1) above (that is, a mouse on COM1, a fax/modem card on COM2, and the PassageWay Service Provider on COM3), you might buy a bus mouse and configure it to use, say, IRQ2 or IRQ5. This would then permit you to move the PassageWay Service Provider onto COM1 (IRQ4), where it then could be used simultaneously with both the mouse and the fax/modem.

Likely candidates for conversion from a serial interface to some other interface include mice (which can be converted to bus mice) and serial printers (which can be converted to an additional parallel printer port).

Workaround 3: If your serial port hardware permits you to select IRQs other than the default ones (IRQ3 and IRQ4), make use of one or more unused IRQs in your system to assign to each COM port a unique IRQ.

This solution is generally not possible for built-in serial ports since these are usually “hard-wired” and cannot be changed. Although most add-on cards containing serial ports permit you to change the IRQs assigned to them, many cards do not let you select IRQs other than IRQ3 and IRQ4. For example, an internal modem card generally has jumpers or switches that permit you to administer the serial interface on the card to be COM1, COM2, COM3, or COM4, but the I/O port addresses and IRQs associated with each of these configurations are usually fixed to the settings in the table.

Fortunately, some serial port add-on cards do permit you to select IRQs other than 3 or 4 (the additional choices are often IRQ2 and IRQ5). If your serial port hardware provides this flexibility — and at least one of the IRQ numbers available as an option is currently unused in your PC setup — you can solve the IRQ conflict directly.

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