GE MDS Master Station Technical Manual page 47

gated to all member sd-nic interfaces. This insures that all SD radio interfaces in the system are
using identical configurations so that interface fail-over is seamless.
To access the full suite of SD configuration options, select the sdms interface from the interfaces
drawer on the left-hand menu.
Understanding the use of Virtual Radio Channels (VRCs)
VRCs allow over-the-air data to be directed to specific interface ports (IP or Serial) on the radio.
Conceptually, this can be pictured as creating "pipes" for delivery of data to the desired radio
interfaces.
VRC works by associating data from a specific port (IP and Serial) with a VRC channel number
(1, 2, or 3). Each port at the receiving end then filters incoming data based on the associated
VRC number.
The Virtual Radio Channel (VRC) feature is only supported in Packet w/MAC modes. It
is not supported in Transparent or x710 mode.
To create the "pipes" that direct data to the desired ports, a route must be established using the IP
Payload Configuration Menu (or payload serial settings on the general configuration menu for
serial data). The default setting is to listen to all channels.) The Talk on parameter is used to
specify the VRC used for sending the data stream over the air, while the Listen to parameter
specifies the VRC(s) for incoming data.
Any combination of the three VRC numbers may be entered in the selection fields. Figure 5-2.
Virtual Radio Channel (VRC) Concept illustrates the relationship between the VRC settings and
the routing of data between units.
Figure 5-2. Virtual Radio Channel (VRC) Concept
MDS 05-6399A01, Rev. E MDS™ Master Station 43