User`s guide

WN-5220-V VideoWall User’s Guide
63
Transmission Speed 9600 BAUD
Transmission Data Data Length: 8, Stop Bit: 1, Parity Bit: None
No hardware or software pacing is used such as DTR/RTS or
XON/XOFF.
The display’s RS-232 port is always active except during the boot
process which is the first 10 seconds after power is applied to the
display electronics.
In single address mode (not when global commands are being used)
the host machine must wait for an ACK, NAK, UNK or ERR response
from the display before sending the next command. When global
commands are sent, the displays will not return a response, so a
delay of ½ second should be maintained between commands to avoid
possible errors.
The protocol for communication to the display consists of a 7 byte
command line as described below.
STX
(1 byte)
IDT
(2 byte)
CMD
(3 byte)
ETX
(1 byte)
Where;
ASCII STX
- Start of transmission character, = 02h
Description Abbreviation Hex Decimal Character Control
Start of Text STX 02 2
Ctrl- B
IDT
- Monitor ID bytes are used to identify which display will receive
the RS-232 command. This is a 2 byte address that is set by the
Group and Unit Monitor ID knobs on the display’s connector panel.
Each knob has 16 possible settings with the Group setting the high
byte and the Unit setting the low byte. The address consists of the
ASCII Alphanumeric characters (0-9, A-F for the Group setting and
0-9, A-F for the Unit setting) providing the means to control up to 256
combinations (00 to FF).
Multiple units can be controlled simultaneously by using the ASCII
character for the asterisk (*) in place of either or both of the IDT
monitor ID bytes. The (*) is a wild card character and provides a
means to control multiple units simultaneously. There are four types
of addressing that are supported.
1. Single address mode
– the entire address is specified: 00, 01, 02,
A2, AA, FF are valid examples. Only the single display that
matches this address responds to it. An acknowledgment is sent
in this mode. Do not set multiple displays to the same address.
2. Group address mode
– the group part of the address is specified,
while the unit part of the address is not: 1*, 9*, A*, F* are valid