GUIDE TO INSTALLATION AND OPERATION
12
| HMP-1801
2.4.3 VDCP Connector
The HMP-1801 can interface to a remote recorder using the VDCP protocol via the RS-422 port on the rear panel.
This interface is implemented on an RJ45 connector to save space.
The HMP-1801 supports a subset of the VDCP protocol. A detailed description of the supported commands is
contained in Appendix 2 to this document, beginning on page 71.
The VDCP response delay of the HMP-1801 is not constant. Particular attention was paid to the “immediate
commands” where it is necessary to respond within a frame.
A window of validity has been defined where the response time is constant and guaranteed. The chart and diagram
following illustrate the concept and show the timing for various video formats.
*720p59.94 is the worst case
•
For VDCP, the 11 ms
gray zone, where the
processing time may be
either 2 or 3 frames, is
to be avoided.
FORMAT
Acceptance
Zone
Windows FPGA
525
10 ms
21 ms
625
17 ms
28 ms
1080i59.94
10 ms
21 ms
1080i50
17 ms
28 ms
*720p59.94
4 ms
15 ms
720p50
6 ms
17 ms