unless otherwise noted, the comments also apply to
Previously, we discussed the analogy between telephone systems and matrix intercom systems – the analogy is not correct in all cases, here are some exceptions.
Figure 5.1 Typical ADAM™ Matrix Connections
In ADAM™ matrix intercom systems, the connection between the matrix and keypanel is normally via three twisted pairs of unshielded cable. As shown in Figure 5.1, one pair carries balanced audio from the keypanel to the matrix, one pair does audio in the opposite direction, and one pair is a
IMPORTANT As eight panels share one physical data line, the matrix must have some means of identifying which panel is sending data to it, and also have some means of addressing messages to one specific panel of the eight. The key word in the previous sentence is “addressing.” Each keypanel in the system must be assigned an address by one means or another. On some keypanels this involves setting “dip switches” to select a “one of eight address” via binary code
If a separate keypanel is attached to each of the 8 ports which share a data line, each panel must have a unique address set which matches the physical port to which the panel is connected. Having a panel with an address different from the physical port to which it is connected will render that panel unusable (in a practical sense, even though the panel may receive audio). Having two or more panels in a given group of 8 with the same address will disrupt all eight panels in that group by causing data collisions on the common data line. This is so important that I will repeat it. Having two or more panels in a given group of eight with the same address will disrupt all eight panels in that group by causing data collisions on the common data line.
At time of initial installation, or system modification, the great majority of anomalies can be traced to improper addressing.
62 H a n d b o o k o f I n t e r c o m S y s t e m s E n g i n e e r i n g
