2.0 The Cable Installation is far more Complex for the Digital Switch.

With a digital switch, the building wiring installation must use a star topology since all voice-streams must be routed as separate lines back to the central digital switch. This means that for every operator input and output channel a bidirectional aural feed must be routed from the operator station to some central point. If stereo positions are required, the amount of cabling is doubled. If adding aural cues from a separate loudspeaker source is required, even more wiring is needed. If giving the operator a communication control panel is required, the wiring may be increased substantially.

This onerous requirement applies not just for all the voice channels, but for any panel I/O (unless some distributed workstation is used for each operator, in conjunction with a separate communications switch). When evaluating alternative solutions, it is common to ignore this very real cost component and treat it as a building cost element. However, this wiring constraint can also be a significant factor when it is necessary to add additional positions to the installation at a later date, or even when relocating positions within the building. In this modern world of technology, the pace of change is accelerating, and any system design that is predicated on remaining unchanged for the next millennium is severely flawed.

By contrast, the DACS RIU/TDM installation is straightforward. Since it employs a single Cat5 cable loop for all audio, aural cue, and I/0 back to a local ethernet node, we can bid it as a turnkey solution including installation, with no major impact upon the price. This ease of installation means that the facility retains the maximum flexibility for making future changes; the sunk cost is minimal.