Omega Vehicle Security DRA-DCC-8 - Manual (Page 7)

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6.2 THE "E" (ENABLE) TERMINAL
For E="1" the unit is enabled, which means that all input vectors are received and
the output is updated. When E="0" the unit ignores any new input vector. The E
terminal is recommended to be used as a strobe for parallel data which has a long
setup time. In this case the following sequence is recommended: prior to applying
a new vector, the E terminal should be set to logical 0 (inhibit state), then the new
input vector should be imposed. Once the new data is set, the E terminal should
be pulsed.
The E terminal is also used for multidrop configuration. The 15 bit vectors are
applied to the units in parallel and the selection is carried out by controlling the
"E" inputs.
7. SERIAL CONTROL MODE
Figure 3.
7.1 RS232c / RS422 SELECT
he DRA-DCC-8 is equipped with two serial
communication ports: The RS232c and the
RS422. A jumper switch at the right side of the
DIP switch array is used to select the required
communication type. See figure 3.
7.2 RS422 TERMINATION
The SW8's ON state terminates the RS422 receiver terminals with a 100
W
load.
In a multidrop configuration, the last (most distant) DRA-DCC-8 unit should be
terminated in order to match the transmission lines.
Note: Only one termination load per RS422 communication link is permissible.
7.3 SERIAL CONTROL SWITCH SETTINGS
S1 S2 S3 S4 S5 S6 S7
BAUD RATE ID CODE * ON
* according to para #5.2
7.4 SERIAL COMMUNICATION PARAMETERS
The communication protocol is 8 bit ASCII, even parity, and one stop bit.
RS-422
RS-232c