M-Audio Biport 2x4s [21/48] Receive interrupt test

• The loopback MIDI cable is incorrectly connected. Check to make

sure that you have a MIDI cable connected between the BiPort MIDI

In and the BiPort MIDI Out selected in the diagnostic program. There

should be no MIDI instruments, mergers, or thru boxes connected to

the BiPort during this test; it is a closed-loop test with one MIDI cable

connected between two MIDI jacks of the BiPort.

• The MIDI cable you are using to loopback data is defective.

• The BiPort is defective. This is extremely rare as the BiPort units are

tested rigorously at the factory before shipping. If you think this is

the case, please contact MIDIMAN Technical Support.

4. Receive Interrupt Test

This test verifies the reception of data from the BiPort under interrupt

(IRQ) control. If this test fails, it is host serial port related. More specifi-

cally it is almost always host IRQ-related.

Most computers use IRQ4 for COM1 and IRQ3 for COM2. If you have

the BiPort connected to COM1 on your computer and have IRQ=4 set in

BI24DIAG.EXE, but it fails the Receive Interrupt Test, you could have an

internal modem connected COM1 or another odd numbered COM port

using the same IRQ. Another possibility is a driver associated with

another device used on the same serial port is adversely affecting the

IRQ. Yet one more possibility is that your serial port IRQ is disabled in

your computer’s BIOS CMOS setup, and simply needs to be switched

on.

If you are unsure what your port IRQ is or how to find out, please see

the section in this manual titled “Selecting a Host Serial Port,” or consult

your computer owner’s manual or computer manufacturer directly.

5. SMPTE I/O Test

This test makes sure that the SMPTE In and Out jacks are functioning

properly. If this test fails, make sure that the cable you have looped from

SMPTE In to SMPTE Out is good, and also properly connected.

PC Drivers and Driver Installation

MIDI application software communicates with the BiPort 2x4s via soft-

ware “drivers.” Basically, a Windows software driver is a special dedi-

cated program that makes a MIDI interface accessible to any Windows