Here is miscellaneous information about IRQs...

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What is an IRQ?  This stands for Interrupt Service Request.  It's usually a jumper-selectable interrupt request that enables the hardware to signal the CPU for service. The CPU (Central Processing Unit) is the component of a computer system that performs instruction sequencing, logic and arithmetic, while also controlling input/output. In a microcomputer, this is generally a single chip.  We need these IRQs to operate computer devices such as the keyboard, hard disk controller, com ports, printer, or some other peripheral device.
In the January, 1998 issue of PC Magazine, Jim Seymour published an article called "The New IRQ Scandal."  His key points are:
  • PC manufacturers "are starting to ship machines fully maxed-out on IRQs."
  • Since 1984 with the introduction of the IBM AT model, there have only been 16 IRQs available.  Most of these are already taken-up by various internal/eternal hardware devices.
  • If an extra IRQ is available, it is often required by a network interface card (NIC).
  • "This is bad news for consumers, especially less-than-expert consumers."
 Why does CTI mention this?

Because in the general 3780 BSC user market, software manufacturers (other than CTI) are still pushing their 3780 software along with expensive internal synchronous interface cards that require specific IRQ settings along with an I/O address.  These synchronous interface cards can cost from $295 to over $1,000 each and are required to "translate" sync input to async.

This problem - the lack or IRQs, has been essentially eliminated by CTI with its introduction of their SyncPack2000e® package which includes a special version of 3780 software that uses an AutoSync® protocol in conjunction with a Hayes® Optima® business modem.

It should be noted that in some cases the need still exists for using a synchronous interface device (either internal or external).  For example, when using old communication protocols such as Bell 201c or Bell 208b.  In these cases the situation calls for a special type of modem that does not support AutoSync protocol.