CDR-3250/80 TECHNICAL MANUAL
3-46
Issue 2.2
Section II. REMOTE CONTROL
Two different interface standards are available for the
CDR-3250/80 receiver: Serial and IEEE-488. The serial
interface includes both unbalanced (RS-232) and balanced
(RS-422) line interfaces. To configure the receiver's
hardware for Serial or IEEE-488 operation, it is only
necessary to change a small plug-in daughter board in the
Digital Module, and the rear panel mounted bus plate with
its associated cable. The control firmware detects the
interface type at power up and then operates it. Refer to
Chapter 2 for installation and electrical characteristics.
Parameters associated with the remote control interface can
be checked and changed from the front panel of the
receiver. For the IEEE-488 interface the only parameter that
may be set is the receiver's talk and listen address. For the
serial interface, the bus address, bus type (RS-232 or
RS-422), baud rate, bus sharing option, and line parameters
may be set. (Line parameters include number of data bits,
number of stop bits and parity options).
NOTE
For remote control operation using the
RCU-3100 remote control unit, refer to
the RCU-3100 Technical Manual.
Each type of interface is described below.
3-8 REMOTE OPERATION USING SERIAL
BUS.
The receiver may be optionally operated under remote
control using a serial bus and a suitable controller. To
operate in this manner, press the LOC/REM key until
CTRL:REMOTE appears on the display. The LOC/REM
key has positive control over the remote control function.
However, the bus controller may allow control or prevent
local control when the receiver is in the REMOTE mode.
Ensure that the communications parameters are set in
accordance with the system requirements. Refer to Chapter
2 for the correct installation procedures. The bus address,
bus type (RS-232 or RS-422), baud rate, number of data bits,
type of parity used, and number of stop bits must match
the requirements of the system controller. Refer to
paragraph 3-7.5.2.2.1 to configure the remote control line
parameters for the serial bus.
3-8.1
Serial Bus Description.
The serial interface
includes both unbalanced (RS-232) and balanced (RS-422)
line interfaces. The control firmware is designed to detect
the interface type (serial, IEEE-488, or none) at power up.
However, it does not detect the type of serial bus. This
must be selected by the operator (refer to paragraph
3-7.5.2.2.1).
3-8.2
Serial Bus Message Format.
All transmissions,
in either direction, conform to the message format shown in
figure 3-9. All transmitted and received characters will be
encoded and interpreted as conforming to the ASCII
character code except for the reply to the TB? (Pan Data
Block Request) message. Refer to the description of the
TB? message in table 3-5 for details.
Each character in the message is passed in an asynchro-
nous serial format as shown in figure 3-10. The number of
data bits, number of stop bits, parity options and baud rate
are all selectable from the front panel of the receiver
through the keypad. These selections are stored in non-
volatile memory. All characters are in ASCII code.
3-8.3
Serial Bus Message Types.
All messages are
divided into two major categories: command messages and
status messages. Each category is discussed in the
following paragraphs:
3-8.3.1
Serial Bus Command Messages.
Command
messages are sent from the controller to the receiver and
are subdivided into two classes as follows:
3-8.3.1.1
Serial Bus Radio Command Messages.
Radio
command messages contain commands that are passed to
the receiver. They may command the receiver to change
operational parameters or to report back operational status.
3-8.3.1.2
Serial Bus Interface Command Messages.
Interface command messages contain commands that are
acted upon by the communications interface in the receiver.
These commands cause the interface to change modes or
report status.
3-8.3.2
Serial Bus Status Messages.
Status messages are
sent from the receiver to the controller and are subdivided
into two classes as follows:
3-8.3.2.1
Serial Bus Radio Status Messages.
Radio status
messages contain information about the operational status
of the receiver. These messages are sent as a reply to radio
command messages that request a status report.
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