Crown Audio IQ-INT3 - Manual (Page 8)

Page 8
IQ-INT 3 IQ Interface
IQ-INT 3 Reference Manual
3 Installation
IQ-INT 3 installation can be divided into the following
major parts: Connecting to one or more IQ Bus loops,
connecting to the host computer or modem, and set-
ting the communication baud rate.
3.1 Connecting to an IQ Bus Loop
The IQ Bus is a serial communication loop designed to
transmit IQ commands and data. As a communication
standard, it is independent of its wiring. This character-
istic allows you to wire an IQ Bus loop with either fiber
optic cabling or with inexpensive twisted-pair wire,
whichever is most appropriate. One IQ System can
have more than one IQ Bus loop, and each loop must
be unbroken for proper operation.
The IQ-INT 3 supports up to four IQ Bus loops. This
makes it possible to divide the system into zones, each
with its own loop. Single and multiple IQ Bus loops
each have their own advantages that are listed next.
Multiloop Advantages
• A break in communication in one loop does not
affect other loops.
• Over 250 IQ components of the same model can
be used in a system.
• The same IQ address can be used more than
once (once for each type of unit on each loop).
Figure 3.1 An IQ System with a Host Computer and an IQ-INT 3
• Larger areas can often be covered without using
repeaters or fiber optic cabling.
Single Loop Advantages
• The IQ-INT 3 can send and receive data slightly
faster using a single loop.
• “Real-time” levels can be displayed for a greater
number of units.
The IQ-INT 3 is designed to work with inexpensive
twisted-pair wire, so it implements the IQ Bus as a 20-
milliamp current loop operating at a baud rate of
38,400. If you want to use fiber optic cabling, contact
Crown’s Technical Support Group for information on
the appropriate transceivers.
Here are some guidelines for twisted-pair wiring:
• An IQ Bus loop must be unbroken to carry
commands and data to and from connected
units.
• Never cross-connect IQ Bus loops. Each IQ
Bus loop is an independent serial communication
circuit. An IQ Bus output is connected to the input
of the first IQ component on the loop. Each unit’s
output connects to the next unit’s input until the
loop returns to the interface where it is connected
to the input for the same loop.