Technovision 421VS Operating Guide
Page 5
CONTROL MODE: 2-line TTL Control
DIP-switch position 1 and 2 must be
OFF
. Control lines
MUST
be kept low
to select the video input.
INPUT #
PIN 1 on CONTROL
PIN 6 on CONTROL
1
HIGH (OPEN)
HIGH (OPEN)
2
Pulled LOW to Ground
HIGH (OPEN)
3
HIGH (OPEN)
Pulled LOW to Ground
4
Pulled LOW to Ground
Pulled LOW to Ground
Example: To select INPUT #2 you must contact pin 1 to ground (pin 5).
Releasing it would return the INPUT to #1.
CONTROL MODE: 4-line TTL Control (dry contact closure)
DIP-Switch position 1 must be
OFF
and position 2 must be
ON
. Input
control lines can be pulled low (
dry contact closure with pin 5
) momentarily
to select the input.
INPUT #
PIN 1
PIN 6
PIN 2
PIN 7
1
PULLED
LOW
HIGH
(OPEN)
HIGH
(OPEN)
HIGH
(OPEN)
2
HIGH
(OPEN)
PULLED
LOW
HIGH
(OPEN)
HIGH
(OPEN)
3
HIGH
(OPEN)
HIGH
(OPEN)
PULLED
LOW
HIGH
(OPEN)
4
HIGH
(OPEN)
HIGH
(OPEN)
HIGH
(OPEN)
PULLED
LOW
Example: To select INPUT2 you can momentarily contact pin 6 to ground
(pin 5).
Page 6
Technovision 421VS Operating Guide
CONTROL MODE: RS232 Control (9600, 8, N, 1)
•
You will have to remove the lid on the 421VS and move Function switch
position 1 to the
ON
position for RS232 control.
•
The protocol is 9600 baud, no parity, 8 bits, 1 stop.
•
The switcher receives data on pin 3 and transmits on pin 8 of the DB9
male connector on the back of the switcher. Data ground is pin 5.
•
On start-up the switcher will transmit "Technovision 421VS".
•
A single byte is sent to the switcher to select the input signal. This byte is
echoed back by the switcher upon receipt of the command.
The protocol of the single byte command to the switcher is as follows:
•
Bits 7 to 4 are always
∅∅
11 (30H)
•
Bits 3 and 2 are the switcher address (0 to 3). Default is
∅∅
•
Bits 1 and 0 are the input select value (I). Value of
∅
=input 1, 1=input 2,
2=input 3 and the value of 3=input 4.
Example for a switcher with the address of
∅∅
(
DEFAULT
):
Input #
RS232 character to transmit to the switcher (address 0)
1
30H (30H+address
∅∅
+
∅
), ASCII "
∅
" , decimal 48
2
32H (30H+address
∅∅
+ 1), ASCII "1" , decimal 49
3
32H (30H+address
∅∅
+ 2), ASCII "2" , decimal 50
4
33H (30H+address
∅∅
+ 2), ASCII "3" , decimal 51
Determining the switcher address:
Address
Value to add
0
0
1
4
2
8
3
12
Example: To select INPUT#3 on the 421VS with the address of 0 (default),
you would transmit (30H+0+3) - the character “3” to the 421VS.
Example: To select INPUT#3 on the 421VS with the address of 1, you would
transmit (30H+4+3) - the character “7” to the 421VS.
