Section 5: Options and Accessories
8197 Instruction Manual
Page 5-13
5.7.3 RS-485 Timing Signals
The Data Sync timing signals are output in RS-485 levels. RS-485 is a balanced
differential transmission requiring twisted pair cable. Cable lengths up to 4000
feet are possible when using cables specifically designed for RS-485
applications, like Belden 9844 or equivalent. These cables have a braided
shield, nominal impedance of 120 ohms, and a capacitance of 12 to 15
picofarads per foot. Refer to Figure 5-5 for a schematic representation of an RS-
485 line driver. Relative to RS-485 specifications the A Terminal (-) is negative
with respect to the B Terminal (+) for a Binary 1. The A Terminal (-) is positive to
the B Terminal for a Binary 0.
B
A
+
-
RS-485 OUTPUT
FIGURE 5-5 DATA SYNC DRIVERS
5.7.4 CTCSS Configuration
The CTCSS outputs are configured using the front panel RS-232 COM port. The
C
TCSS
T
one
C
ontrol command, CTC, is used to read or set the configuration or
provide a listing of all CTCSS frequencies available.
In the following command descriptions, characters in
Bold Italics
are keys typed
by the user. Terminate all command lines with the enter key. The enter key is
represented by
<ent>
. The responses from the Model 8197 are in
Italics
.
Configure the terminal for ANSI, 9600 baud, and xon/xoff flow control. The
character structure is ASCII, 1 start, 8 data, 1 stop and no parity.
To retrieve the current CTCSS output configuration, issue the
CTC
command as
shown below:
Type:
CTC <ent>
Default Response:
CTCSS GENERATOR SETTINGS
1= XZ (67.00Hz) 2= XZ (67.00Hz) 3= NOT PRESENT 4= NOT PRESENT