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Iq interf ace modem, 2 connecting to a host computer, 1 connecting to a modem – Crown Audio IQ-INT II User Manual

Page 9: Pin cable, Standard 9-pin null modem, Pin to 25-pin cable

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IQ-INT II IQ Interface

Page 9

Reference Manual

1
2
3
4
5
6
7
8
9

Refer to the documentation

provided with your RS422

interface to identify the

correct pin connections.

Transmit Data (TXD+)
Transmit Data (TXD–)
Receive Data (RXD–)
Receive Data (RXD+)
Signal Ground (GND)
Clear to Send (CTS–)
Clear to Send (CTS+)
Request to Send (RTS+)
Request to Send (RTS–)

PIN

The female interface connector is shown as it appears.

IQ-INT II

1

5

6

9

PC (RS422)

5

1

9

6

Fig. 3.8 Standard RS232 Wiring

Fig. 3.9 RS422 Wiring

3.2 Connecting to a Host Computer

There are two main communication standards supported
by the

IQ-INT II for serial communication with a host

computer. They are RS232 and RS422.

RS232 is commonly used with IBM

®

PCs and

compatibles. Because it uses unbalanced signal wiring,
it cannot be used for distances over 50 feet (15.2 m).
RS422 uses balanced signal wiring and can be used
for distances up to 2,000 feet (610 m) with data grade
cable.

Although not very common, RS423 communication can
also be used. It is a hybrid of RS232 and RS422 that
uses the unbalanced transmitter (TXD) wiring of RS232
and the balanced receiver (RXD) wiring of RS422. It
provides signal ground isolation between the transmit
and receive lines. With a proper cable, it can be used
over a greater distance than RS232, but over a shorter
distance than RS422. Contact the Crown Technical
Support Group if you want to use RS423 and need more
information.

The following illustrations show how to connect the

IQ-

INT II to the most common host serial ports:

Not used

ReceiveData (RXD)

Transmit Data (TXD)

Signal Ground (GND)

Request to Send (RTS)

Clear to Send (CTS)

2
3
5
7
8

2
3
5
7
8

Transmit Data (TXD)
Receive Data (RXD)
Signal Ground (GND)
Clear to Send (CTS)
Request to Send (RTS)

PIN

PIN

Cable connectors are numbered as they appear from the front.

PC (RS232)

IQ-INT II

5

1

9

6

1,4,6,9

5

1

9

6

3.2.1 Connecting to a Modem

The

IQ-INT II is also modem compatible. The IQ-INT II

periodically sends out an “AT” command string {ATS0=1}
that automatically initializes a connected modem to its
max baud rate and auto-answer mode. A standard null
modem cable should be used between the interface
and modem with the exception of pin 4. Pin 4 of the 9-

pin RS232/242 connector on the back of the interface
should NOT be connected.
This pin implements one
side of the RS422 type line receiver and, as such, allows
balanced wiring on a 9-pin connector. This configuration
is not compatible with some 232/null modem
applications. Refer to the diagram below for modem
wiring detail.

IQ INTERF

ACE

MODEM

9-PIN CABLE

MALE

MALE

1

1

2

2

3

3

4 (MUST BE DISABLED)4

5

5

6

6

7

7

8

8

9

9

STANDARD

9-PIN NULL MODEM

FEMALE

MALE

1

1

2

2

3

3

4

4

5

5

6

6

7

7

8

8

9

9

9-PIN to 25-PIN

CABLE

FEMALE

MALE

1

8

2

3

3

2

4

20

5

7

6

6

7

4

8

5

9

22

Fig. 3.10 Modem Hookup