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USER MANUAL
HCO-3931 |
15
REF IN
– Studio Reference Input
For external synchronization, connect a black studio reference signal to the BNC labeled
REF IN
.
Two reference signal formats are supported:
For 59.94 fps: 525 (SMPTE 170M / 318M NTSC black burst)
For 50 fps: 625 (ITU 624-4 PAL black burst)
GPIO Connector
The rear panels of the HCO-3931 include a GPIO interface that allows control of the switch process. When connecting
the HCO-3931 to an automation system, be aware of the following:
1.
The HCO-3931 card senses the presence of an external power supply voltage on the GPIO input. Any voltage
greater than 1 V will silence the
GPI Connector Power
alarm, when this alarm is enabled.
2.
GPIO inputs trigger on a momentary pulse. To be recognized without ambiguity, a GPIO trigger pulse should
have a duration of at least 50 ms.
Figure 5
GPIO input trigger pulse timing