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
1HIGH (OPEN) HIGH (OPEN)
2Pulled LOW to Ground HIGH (OPEN)
3HIGH (OPEN) Pulled LOW to Ground
4Pulled 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
1PULLED
LOW HIGH
(OPEN) HIGH
(OPEN) HIGH
(OPEN)
2HIGH
(OPEN) PULLED
LOW HIGH
(OPEN) HIGH
(OPEN)
3HIGH
(OPEN) HIGH
(OPEN) PULLED
LOW HIGH
(OPEN)
4HIGH
(OPEN) HIGH
(OPEN) HIGH
(OPEN) PULLED
LOW
Example: To select INPUT2 you can momentarily contact pin 6 to ground
(pin 5).
Page 6Technovision 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)
130H (30H+address∅∅ + ∅), ASCII "∅" , decimal 48
232H (30H+address∅∅ + 1), ASCII "1" , decimal 49
332H (30H+address∅∅ + 2), ASCII "2" , decimal 50
433H (30H+address∅∅ + 2), ASCII "3" , decimal 51
Determining the switcher address:
Address Value to add
00
14
28
312
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.
