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CHAPTER 3: Functions
3. Functions
This chapter describes the functions of the Pro Switching System, including
switching and patching options and the monitoring bus. The chapter also
describes the system configuration options.

3.1 Switching and Patching

The Pro Switching System offers these switching and patching options:
• A/B switching
• Three-cavity patching
• Four-cavity patching
3.1.1 A/B S
WITCHING
A/B switches have three ports: A, B, and COMMON. You can connect the line at
the COMM IN port to the line at the A port or the B port. Figure 3-1 shows an A/B
switch in which the COMMON port is connected to the A port.

Figure 3-1. A/B Switching.

The switch uses latching relays, which remain in the last switched position if the
power fails.
A/B switches are available for use with the following interfaces: RS-232/V.24,
RS-530, V.35, DB15, RJ-11, and RJ-45.
3.1.2 T
HREE
-C
AVITY
P
ATCHING
These cards have three patch cavities: COMP, MODEM, and MON. Figure 3-2
shows three-cavity patching. Normally, the DTE is connected to the DCE.