Crown Audio PSI - Manual (Page 10)

Page 10
IQ–PSI IQ Pocket Serial Interface
the IQ–PSI connector to a 5-pin DIN input connector on
an IQ P.I.P .
The IQ components in a Crown Bus loop are wired
sequentially. The loop begins and ends with the
IQ–PSI .
Fig. 3.8 RS232 Cable Wiring
Note: A 9-pin to 25-pin adapter will be needed if the host
computer you plan to use has a 25-pin connector in-
stead of a 9-pin connector.
3.3.1 Setting the Baud Rate
Before communication can take place between the IQ–
1 2 3 4
SW4
38400
19200
9600
4800
BAUD
RATE
1 2 3 4
ON
(DOWN)
Fig. 3.9 Baud Rate Settings
IQ–PSI
IQ Component
IQ Component
IQ Component
CROWN BUS LOOP
Fig. 3.7 Crown Bus Wiring “Loops” from the
Output to the Input of Each IQ Component
The output of one IQ component “loops” to the input of
the next and so on. This is shown below:
3.3 Connecting to a Host Computer
Most IBM ® PCs have a serial or “com” port. This is
actually an RS232 serial port. Because RS232 uses
unbalanced signal wiring, it cannot be used for dis-
tances over 50 feet (15.2 m).
Not used
Receive Data (RXD)
Transmit Data (TXD)
Signal Ground (GND)
Request to Send (RTS)
Clear to Send (CTS)
2
3
5
7
8 3
2
5
8
7
Not used
Transmit Data (TXD)
Receive Data (RXD)
Signal Ground (GND)
Clear to Send (CTS)
Request to Send (RTS)
PIN PIN
Connectors are numbered as they appear from the outside.
(1, 4, 6, 9)
PC Serial Port
5 1
9 6
IQ–PSI RS232
5 1
9 6
The following illustration shows how the RS232 cable of
the
IQ–PSI is wired:
PSI and a host computer, the baud rate must be set with
the 4-segment DIP switch (SW4) located inside the
battery compartment. (See Figure 3.9 below.) The high-
est baud rate possible should be used (typically
38,400).
Caution: Turn off the IQ–PSI before changing the
baud rate setting.
Important: The baud rate of the IQ–PSI and the host
computer must be the same. Any mismatch will
prevent communication from taking place.
The communication parameters of the host computer
are set by the IQ software. Please refer to the appropri-
ate software manual for details.
Here are some important guidelines when configuring
serial communication:
• Use the same communication standard at each
end. The IQ–PSI supports only the RS232 stan-
dard. Other standards such as RS422 should
not be used by the host computer. (Refer also to
the appropriate IQ software manual.)
• Set the IQ–PSI and the host computer to the
same baud rate.
• The IQ–PSI baud rate can be set as high as 38.4
K (38,400) baud. Use the highest baud rate pos-
sible, but be aware that the communication cir-
cuitry (UART) in some PCs cannot function over
9600 baud. We recommend that the host com-
puter have a serial interface with a 16550-com-