Q u i c k G u i d e :
Unison AV/Serial Interface v1.0.0 Quick Guide
Unison AV/Serial Interface v1.0.0 Quick Guide
Page 9 of 9
Electronic Theatre Controls, Inc.
Packet Mode Help
Packet Mode is a simple way to ensure that only full serial messages are executed at the
AV/Serial Interface station. Packet Mode requires a preamble to tell the station how many
bytes the command will be. As explained in
Configuration Settings (nn.cf) on page 6
, the
preamble is a single byte with the eight-bit set to one and the lower bits representing the
number of bytes. The single byte preamble is always greater than 128 and an ASCII code
that has no direct keyboard equivalent.
Below are examples of different command sizes and the required preamble. You can type
the preamble character by holding the Alt key while typing the 4-digit number listed while
using a terminal emulator such as Hyper Terminal. You will see the display character if you
have “local echo” turned on in your terminal application.
These are two important commands (including the preambles) to know. The parenthesis
and plus sign are not typed. They represent the characters to type while holding the Alt
key.
To turn off Packet Mode from within Packet Mode:
•
(Alt+0133)SC5.0
To turn on Echo Mode (which suspends Packet Mode):
•
(Alt+0133)SC1.1
In Hyper Terminal, you turn on “local echo” here:
Alt +
Display
Character
Number
of Bytes
Command
0136
ê
8 byte
S
F
1
2
.
1
0
0
0135
ç
7 byte
S
F
1
0
.
5
0
0134
å
6 byte
S
B
1
0
.
1
0133
à
5 byte
S
C
5
.
0
0132
ä
4 byte
G
B
1
2
0131
â
3 byte
G
F
3
0130
é
2 byte
G
V
0129
ü
1 byte
Esc
ACK
♠
Successful
Packet Mode
Responses
NAK
§
Unsuccessful
1 0 0 0 0 1 0 1
8 7 6 5 4 3 2 1
Bit Location
Value
Binary Number
128 64 32 16 8 4 2 1
