Module Mixing; Support For Ddc (Display Data Channel) - ADDER AdderLink AV series Manual

AdderLink AV200 pair
The AdderLink AV200 transmitter and receiver pair operate in a similar manner
to the AV100 series, with the addition of an RS232 serial port. The serial port
of the source PC is presented at the AV200 receiver for use by a remote device
such as a touch screen terminal. The AdderLink AV200 models are designed
primarily for single point to point operation although
they can provide further video/audio expansion via
transmitter cascade connections (the serial
connection is not expandable).
VIDEO
200
PC
AUDIO
RS232 SERIAL
TRANSMITTER
POWER
AdderLink AV200 transmitter and receiver pair driving two remote displays and
speakers plus a serial device, in addition to a local monitor and speaker set

Module mixing

Most of the AdderLink AV modules can be mixed together in various
combinations quite freely. For instance, an AV104 transmitter can drive mixtures
of AV100 and AV101 receivers. Similarly, an AV100 transmitter can control
single or cascaded AV101 receivers. An AV100 receiver can also be cascaded
from an AV101 receiver, although the reverse is not true.
However, the AV200 pair differ from the other modules because they send serial
port signals across the CATx link and so MUST NOT be cross connected (via a
CATx link) with any other non-AV200 modules. The AV200 transmitter can be
used as part of a transmitter cascade with other AV transmitter types. However,
the serial port of an AV200 transmitter cannot itself be cascaded. Therefore, if
an AV200 transmitter is involved in a cascade, it should be placed as the primary
transmitter, connected directly to the source PC system.
RS232
DEVICE
200
CATx LINK
UP TO 300m
RECEIVER
POWER

Support for DDC (Display Data Channel)

The Display Data Channel standard allows video monitors to define their
characteristics so that the source computers to which they are connected can
optimise their video outputs accordingly. By their nature, the AdderLink AV
extenders enable multiple video displays to be attached to a single source
computer. This causes a complication for handling the DDC standard, however,
in characteristic style we have devised an elegant solution, as detailed below.
Whenever an AdderLink AV transmitter is powered on, it checks its local video
port for a working display monitor with DDC information. The following strictly
ordered actions occur to automatically locate the most suitable DDC data:
• If a display monitor is discovered on the local video port of the transmitter,
the DDC data are cloned from it and stored within the transmitter.
• If no display monitor is discovered on the local video port of the transmitter,
the DDC data held within the transmitter will remain unchanged.
• If the DDC data or clock lines of the transmitter's local video port are
discovered to be connected to ground, then a default set of DDC data will
be reloaded and used.
After the initial search period, the stored DDC data are then presented to the
video port of the source computer. When transmitters are cascaded, only the
primary transmitter (the one connected to the source computer) will perform the
search for DDC data.
AdderLink AV transmitters hold two pages of DDC data in order to support the
most advanced display monitors. The DDC data are held within non-volatile
memory so that they are retained when power is removed.
The manner in which the transmitters search for suitable 'DDC donors'
could have an impact if your installation contains display units with differing
capabilities. Generally, you should arrange for the display monitor with the
most representative capabilities of your whole installation to be the one that
the transmitter locates on its local port, either initially (and temporarily) while
commissioning or permanently.
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