Panasonic DBS 576 Technical Manual page 58

Chapter 2. System Overview
AEC/8 card (VB-44620): Analog Extension Card
The AEC/8 card is an extension line interface accommodating unit for standard
telephones (SLT). The AEC/8 card is mounted on a flexible slot to connect a
standard telephone (SLT) to the system.
The AEC/8 card has an 8-circuit analog extension line interface, and provides such
functions as call signals from a standard SLT, detection of dialing (10 pps/DTMF)
and speech.
The supply voltage to a standard SLT is +24V, and a ringer circuit is built-in.
The duration of one callup signal from the built-in ringer circuit is a maximum one
second. Control is in three phases when eight trunks are simultaneously called up:
the first phase for the first to third circuits, the second phase for the fourth to sixth
circuit, and the third phase for the seventh and eighth circuits.
The major specifications on wiring are as follows:
• Supply voltage/current for speech path: +24 V/25mA or more
• Loop resistance: 100 Ohms or less
• Ringer signal frequency: 20Hz rectangular wave
• REN: 2
• CPC (Positive AEC Disconnect) control possible
• Ring trip detection possible
Figure 3-25. AEC/8 card
2-36 DBS 576 (USA), issued 6/2/98
Section 300-Installation
576-13-300