AT&T AT&T manual Port Circuit Pack Common Circuitry

The NPEs do switching network functions for the port circuits. Under control of the on- board microprocessor, an NPE can connect a port circuit to any one of the TDM bus time slots. More specifically, it allows a port circuit to talk on one time slot and listen to the same time slot (NPE sidetone) and on up to four other time slots at the same time. In 2- wire circuits that provide their own sidetone, the NPE sidetone is not used.

Circuit Pack Address Leads: Seven leads (BA0-BA6) are tied to Corresponding logic levels to uniquely identify each CP slot in the system, including multiple cabinet systems. The logic values on leads BA4 and BA5 are used to identify the cabinet (Cabinet 1, 2, or 3) and are tied via the cabinet address plugs to either +5V de or ground, as appropriate. Lead BA6 is tied to ground.

			●
TDM	❘	BUS
	❘
BUS		BUFFERS
LEADS	❘

CIRCUIT	❘
PACK	❘		SAKI
ADDRESS
	❘
LEADS
	LEDS	RED
		GREEN
		YELLOW

NPE(S)

●

●

R A M

ON-BOARD

MICRO-

PROCESSOR

PORT

SPECIFIC

CIRCUITRY

Figure 3-7. Port Circuit Pack Common Circuitry

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