Grass Valley 2200 - Manual (Page 92)

5-2
Section 5 Ñ Digital Effects Interface
NOTE: The switcher relies on the key half of an aux bus pair to be connected to
the same transforming channel as its video half. This interface makes no provision
for use of the key side of a switcherÕs aux bus to feed a second video channel. While
basic functionality can be achieved in this mode, functions such as effects send,
front/back switching and tally will not function properly. Tektronix accepts no
responsibility for interfaces which do not adhere to this constraint.
¥ The term ÒTally,Ó as used here, means that the switcher can receive a message
from the DPM indicating whether the DPM is on-screen or not, and the
switcher can use this information to tally sources feeding the DPM, providing
proper panel and camera tally.
NOTE: The DPM informs the switcher whether or not its image is on screen
without regard to whether the DPM itself is on air. The switcher computes the on-
air tally based on the on/off screen information and whether or not the DPM
output is on air.
¥ Distinguishing between the terms ÒsourceÓ and ÒinputÓ: ÒSource mappingÓ
provides a level of indirection between the switcherÕs physical inputs and a
source selection panel button. Input 20 could be mapped to button 1. ÒInputÓ
would then refer to the physical entity, and ÒsourceÓ to the button and to what
is stored as part of the switcherÕs effect.
Source information exchanged with the DPM is the logical ÒsourceÓ form of
the information that is usedÑnot the physical input. The switcher translates
this internally to a physical input.
NOTE: The term ÒcrosspointÓ can be misleading, meaning both source and input
at different times. In this documentation, the term crosspoint refers to the actual
switching matrix used in routing signals.