www.aja.com
122
FS4 Frame Synchronizer/Converter v1.1
Appendix B: FS4 Pinouts
GPI Pinouts
General Purpose Interface Inputs and Outputs are available on the FS4 back panel to
provide contact closure control. GPI Inputs can control FS4 functions, while GPI outputs
can control external equipment (i.e. alarms).
The GPI inputs and outputs are electrically isolated from power and ground on the FS4
frame. There are four inputs and four outputs. Electrical isolation is provided for up to
four pieces of external equipment.
The following guidelines apply to the four GPI inputs and outputs:
• GPI In 1 and GPI Out 1 share a common isolated ground on pin 24 (GPI GND 1),
• GPI In 2 and GPI Out 2 share a common isolated ground on pin 10 (GPI GND 2).
• GPI In 3 and GPI Out 3 share a common isolated ground on pin 21 (GPI GND 3).
• GPI In 4 and GPI Out 4 share a common isolated ground on pin 7 (GPI GND 4).
• Pin 13, local chassis ground, may only be used as references when isolation is not
required.
• All four GPI inputs are internally pulled high through a 10K ohm resistor to an isolated
+5V supply, so that a relay contact closure or any device sinking at least 0.4 mA to
ground will register a logic low.
• All four GPI outputs are +5V TTL compatible, sourcing up to 6mA and sinking up to
4mA each.
The following illustration shows typical external wiring to the GPI connector. The GPI
inputs require some kind of contact closure between the input pin and the input ground
pin to register the logic low that triggers the GPI input.
You can connect the outputs to TTL buffers that communicate the GPI output logic levels
to other devices. For example, you could use an opto-isolator controlling a relay to
activate other equipment as shown below.
Table 12. DB-25F GPI Input and Output Pinouts
Pin
Function
Pin
Function
1
NC
14
NC
2
NC
15
NC
3
NC
16
NC
4
NC
17
NC
5
NC
18
NC
6
NC
19
NC
7
GPI GND 4
20
GPI Out 4
8
GPI In 4
21
GPI GND 3
9
GPI Out 3
22
GPI In 3
10
GPI GND 2
23
GPI Out 2
11
GPI In 2
24
GPI GND 1
12
GPI Out 1
25
GPI In 1
13
Ground
