TASCAM's AV-452 has a serial port capable of
operating in standard RS-232, RS-422 or RS-485
protocols which offers access to most switches and
indicator status on the AV-452. The AV-452 saves
resources on recursive scanning with a "query all"
command and by generating status replies on status
changes. An additional RS-232 command allows IR
strings to be learned for projector control, outlined
separately in: AV-452_IR_PRG.pdf.
AV-452
Serial Control Specification
• Channel Mute or Dim Command & Status
• Complete AV Routing Command & Status
• Amp A and B In/Out Command & Status
• Intercom and Cascade Command & Status
• Room Volume Up/Down Commands
• "Query All Status" Macro Command
• Dip Switch Setting and EMG Circuit Status
• Uses RS-232, RS-422, or RS-485 Protocol
• Assignable Address for RS-485
• Generates Status Commands on State Changes
• Command to Program Outbound IR Strings
(For this feature, see AV-452_IR_PRG.pdf)
SERIAL ROTARY DIAL SETTING AND CABLE PIN-OUT
Settings and Voltages
Note: The rotary control and most dip switches are only
scanned at power-up. You will need to turn the AV-452 off
and back on for any changes to take effect.
Under the security panel, there is a rotary dial that
determines the machine ID (address). This allows multiple
AV-452 machines to be connected to a single serial line and
still be addressed individually. If you are not using multiple
machines, this should probably be set to "1".
The RS-422 and RS-485 operation follows normal
specifications. However, RS-232 operation is a modification
of the RS-422 port. It operates at 0-4.5V, rather than ±9V.
This will operate normally with most equipment, such as old
control systems or PC computers. If you have trouble with
RS-232, try switching to RS-422 if you can to see if that
solves the problem.
Cable Pin-Out, and Control System Settings
Connector shown from perspective of the rear panel female
connector. The male connector for your cable will be the
mirror image of this diagram.
Connector:
Port Speed:
Command Spacing:
Character Length:
Parity:
All features and specifications are subject to change without notice. Contact your local TASCAM representative for the latest information.
Page 1 of 8
AV-452_RS-232_spec.pdf
031104
COMMAND STRUCTURE
Preamble
.LF..0NcA
0Ah 2Eh2Eh2Eh50h63h4Ch30h 30h
Address
String
Type
Parameter
AV-452 Serial Control Specification
r
e
Del
t
mi
i
Example Command of
Mute Channel 1, bypassing
machine address.
e
u
al
V
0
0CR1.
30h0Dh31h2Eh
Preamble - All command strings for the AV-452 begin with
a line feed (0Ah).
Period Spacers - The four main data fields (Address,
String Type, Parameter and Value) begin with a period
(2Eh). This was mainly put in to make the string easier to
read when coding. However, you can use the period to
parse the string into the four major elements. Since the
strings are always the same length, so you can also use
byte position.
Address - Since the AV-452 can sit on an RS-485 line with
other devices, the AV-452 is "addressable". This address
corresponds to a rotary dial on the rear panel, underneath
the security panel. If you send an address in the
command, the AV-452 will only respond if the address
matches the position of the rotary dial.
If there is only one AV-452 on the line, you can use "NA"
(50h 4Ch) as an override on the machines. That tells the
AV-452 to listen to the command regardless of its address.
It should be noted that status replies from the AV-452 will
always include the machine's individual address. So, if you
are using bidirectional communication from the AV-452, the
programmer and installers should agree upon the address
to be used.
String Type - This section indicates whether the string is a
command, status query, or return status string. A
lowercase "c" (63h) indicates a command for the AV-452,
"q" (71h) indicates a query for the AV-452 to respond to,
and "s" (73h) indicates a status return string from the AV-
452. In the example string above, the lowercase "c"
indicates it is a command.
Parameter - This determines which function on the AV452 is being controlled, queried, or reported. In the
example above, parameter "00" (57h 44h) refers to the
mute control for mic channel 1. (The complete list of
parameter numbers can be found below.)
Value - This is the desired the status of the parameter (or
the current parameter status in a reply). For status
queries, this should be set to "00" (30h 30h). In the
example above, "01" (30h 31h) indicates Mute 1 on.
Delimiter - All command strings for the AV-452 end with a
carriage return (0Dh).
All features and specifications are subject to change without notice. Contact your local TASCAM representative for the latest information.
Page 2 of 8
AV-452_RS-232_spec.pdf
031104
MIC CHANNEL MUTE
AV-452 Serial Control Specification
The command structure for mute and mute status requests
are listed below.
When the AV-452 receives a command for a channel mute,
it will reply with a status command of the new status,
indicating the change was made. Status commands are
.
MUTE CHANNEL 1 OFF
MUTE CHANNEL 1 ON
QUERY MUTE 1 STATUS
STATUS - MUTE 1 OFF (ID 1)
STATUS - MUTE 1 ON (ID 1)
MUTE CHANNEL 2 OFF
MUTE CHANNEL 2 ON
QUERY MUTE 2 STATUS
STATUS - MUTE 2 OFF (ID 1)
STATUS - MUTE 2 ON (ID 1)
MUTE CHANNEL 3 OFF
MUTE CHANNEL 3 ON
QUERY MUTE 3 STATUS
STATUS - MUTE 3 OFF (ID 1)
STATUS - MUTE 3 ON (ID 1)
MUTE CHANNEL 4 OFF
MUTE CHANNEL 4 ON
QUERY MUTE 4 STATUS
STATUS - MUTE 4 OFF (ID 1)
STATUS - MUTE 4 ON (ID 1)
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
also generated whenever the function changes. For
instance, if someone presses the MUTE button for channel
1, uses the IR command or relay control to toggle MUTE 1,
or uses an RS-232 command to change MUTE 1, the AV452 will generate a status command on its own. This
reduces the need for recursive scanning routines.
All features and specifications are subject to change without notice. Contact your local TASCAM representative for the latest information.
Page 3 of 8
AV-452_RS-232_spec.pdf
031104
AV CHANNEL
AV-452 Serial Control Specification
The AV channel of the AV-452 offers control and status on
DIM A/V, the seven A/V source selection items and the REC
MONITOR control. In a related item, there is also status
information on the AUX IN source type.
As with the other commands, the AV-452 will generate
status commands when these items are changed. Note
that the AUX IN TYPE status is read only... you cannot
control it from an external source.
A/V CHANNEL DIM
DIM AV significantly reduces the volume of the A/V
channel. The command structure for this follows the same
.
AV CHANNEL DIM OFF
AV CHANNEL DIM ON
QUERY AV CHANNEL DIM
STATUS - AV DIM OFF
STATUS - AV DIM ON
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
behavior as mic MUTE - the status strings will be generated
any time the status changes, or when it is queried.
This controls the five buttons on the AV channel strip that
handle the routing of audio/video sources. This includes
CASS, CD-RW, DVD, VCR, and AUX, shown at right.) These
work like a home receiver; one of these five buttons will be
active at all times. In the signal flow diagram, this switch
is in the bottom center.
Parameter 12 - REC MONITOR Switch:
Under normal operations, the REC MONITOR switch would
be set to SOURCE. That means the audio source selected
in the AV channel will be sent to the CD-RW, CASS and VCR
outputs on the AV-452. REC MONITOR also offers the
ability to force the cassette or CD-RW to the record out,
allowing you to monitor the return from the recorder. This
is helpful when creating dubs from one unit to another to
change formats, rearrange content on media, or create a
back-up.
Parameter 5 - RGB 1 and RGB 2:
All of the sources with video content (DVD, VCR, AUX,
RGB1 and RGB2) can learn IR commands for a projector.
These codes will be emitted through a rear panel IR driver.
This allows the AV-452 to control the projector source.
The RGB1 and RGB2 buttons do not route signal internally.
These buttons are only intended to learn IR commands to
be sent to a projector (or another external switcher).
These buttons illuminate when
pressed. When another video source
is selected - such as DVD, VCR, or
AUX IN - the RGB buttons will turn
off. This behavior allows the AV-452
front panel to show the current status
of external video switching.
Parameter 17 - AUX IN Type:
This controls the logic of the AUX
INPUT. If the AUX INPUT is set to be
an audio only source, it will not
change the video routing when AUX
IN is selected. However, if AUX
INPUT is set to be an A/V source,
then the AUX IN video source is
routed. This switch is a read only
control.
All features and specifications are subject to change without notice. Contact your local TASCAM representative for the latest information.
Page 6 of 8
AV-452_RS-232_spec.pdf
031104
AMP A, AMP B, INTERCOM & CASCADE
AV-452 Serial Control Specification
The AMP A, AMP B INTERCOM and CASCADE buttons work
just like the MUTE buttons for the channels. These just
have on and off states, and offer the same type of tally
information. The examples are given below for AMP A, just
change the parameters numbers for AMP B "08" (30h 38h),
INTERCOM "09" (30h 39h) or CASCADE IN "10" (31h 30h).
It should be noted that AMP A and AMP B buttons do not
power the amplifiers on and off... these buttons are mute
.
AMP A OFF
AMP A ON
QUERY AMP A
STATUS - AMP A OFF (ID 1)
STATUS - AMP A ON (ID 1)
AMP B OFF
AMP B ON
QUERY AMP B
STATUS - AMP B OFF (ID 1)
STATUS - AMP B ON (ID 1)
INTERCOM OFF
INTERCOM ON
QUERY INTERCOM
STATUS - INTERCOM OFF (ID 1)
STATUS - INTERCOM ON (ID 1)
CASCADE OFF
CASCADE ON
QUERY CASCADE
STATUS - CASCADE OFF (ID 1)
STATUS - CASCADE ON (ID 1)
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
controls feeding the amps. These amps do have a power
switch in the rear separate from the main power, and there
is no status information on that switch.
Also, the CASCADE functionality changes with dip switch
settings on the rear panel of the AV-452. (One mode mixes
the cascade input with the internal system, the other mode
replaces the internal signal with the cascade port.) See the
AV-452 Owner's Manual for more detailed information.
All features and specifications are subject to change without notice. Contact your local TASCAM representative for the latest information.
Page 7 of 8
AV-452_RS-232_spec.pdf
031104
ROOM VOLUME LEVEL (COMMAND ONLY)
AV-452 Serial Control Specification
The ROOM VOLUME control adjusts the level that comes out
the SPEAKER OUTPUT and STEREO OUTPUT. The knob is
motorized, and can be controlled externally. Commands
.
ROOM VOLUME DOWN
ROOM VOLUME UP
LF
0Ah
LF
0Ah
2Eh
.
2Eh
EMG BREAK (READ ONLY)
When the AV-452 detects an emergency alarm is activated
(by the relay activation on the EMG port), the AV-452 will
shut down all local audio. All the LEDs flash on the front
panel when in this status. For the control system, this
.
QUERY EMG
STATUS - NORMAL (ID 1)
STATUS - EMG BREAK (ID 1)
LF
0Ah
LF
0Ah
LF
0Ah
2Eh
.
2Eh
.
2Eh
DIP SWITCHES (READ ONLY)
are available for up or down; there is no status message for
this command - it acts just like the infrared command. One
volume command will turn the dial for 1/2 second.
N
4Eh
41h
N
4Eh
41h
status is the key to recognizing the situation. As with the
other commands, these status messages are sent when the
status changes.
N
4Eh
41h
0
30h
31h
0
30h
31h
.
A
2Eh
63h
.
A
2Eh
63h
.
A
2Eh
71h
.
1
2Eh
73h
.
1
2Eh
73h
c
c
q
s
s
.
2Eh131h
.
2Eh131h
.
2Eh131h
.
2Eh131h
.
2Eh131h
8
38h
8
38h
6
36h
6
36h
6
36h
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
0
30h
0
30h
0
30h
0
30h
0
30h
0
30h
1
31h
1
31h
0
30h
1
31h
CR
0Dh
CR
0Dh
CR
0Dh
CR
0Dh
CR
0Dh
Some of the dip switches on the rear panel are logic
controlled, and will emit their status when the "request all"
status is sent. These switches are only scanned when the
.
STATUS - HPF OFF (ID 1)
STATUS - HPF ON (ID 1)
STATUS - CASCADE EXCL (ID 1)
STATUS - CASCADE MIX (ID 1)
STATUS - MONO OFF (ID 1)
STATUS - MONO ON (ID 1)
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
LF
0Ah
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
.
2Eh
QUERY ALL STATUS
This command triggers the AV-452 to send all status
messages for a complete update on the system. This is
.
QUERY ALL STATUS
LF
0Ah
2Eh
unit first turns on. It may be desirable to have the control
system alert an AV tech if these settings do not match the
normal setting, in case someone tampered with them.
0
30h
31h
0
30h
31h
0
30h
31h
0
30h
31h
0
30h
31h
0
30h
31h
great for control systems when the unit has not been
monitored in a while, so all functions can become known.