Ringing SLIC's For ISDN, PBX and Internet Telephony

Silver Telecom's Ag1250/Ag1255 dual ringing SLICs and Ag1450/Ag1455 quad ringing SLICs
are integrated components which ease connection from telephone and modem lines to digital
networks.

The circuits provide the ringing signal to the terminal equipment, without an external
ringing generator or relays. On-hook transmission is supported for caller line ID applications
and battery polarity reversals can be applied to the telephone line, to support many signaling
schemes.

Working from single 5V system side power supply, the SLICs' feature per channel intelligent
power-down. This puts each SLIC into a standby mode, minimising power supply cost, while
detecting the off-hook condition.

Power consumption is typically less than 50mW/channel. Use of the 'loop open' feature will
reduce power consumption further.

The devices are designed to work on short to medium length lines, with programmable loop
current and off-hook detection thresholds. They can switch battery voltages to reduce power
dissipation on very short lines.

The Ag1250 and Ag1450 offer fixed 600 ohm output impedance while the Ag1255 and Ag1455
offer programmable impedance and network balance to suit any international market.