A hybrid integrated trunk and subscriber line interface
A two-chip hybrid integrated trunk and subscriber line interface has been fabricated for voice and data applications. This paper will discuss features including a programmable battery feed with lightning protection, battery-reversal signaling, 2-4 wire conversion, loop closure detection and power down capability.
A high-voltage IC for a transformerless trunk and subscriber line interface
A new high-voltage, junction-isolated, complementary bipolar technology has been used to fabricate an IC for a transformerless trunk and subscriber line interface. The new technology provides both vertical p-n-p and n-p-n transistors with BV/SUB CE0/ greater than 60 V, betas of 100, and f/SUB T/'s of 200 MHz. It permits the straightforward op amp realization of a new op amp circuit configuration in transformerless line circuits. The new configuration uses the high-voltage IC plus some low voltage control circuitry to provide limited current battery-feed, loop-closure detection, reverse-battery signaling, two-wire to four-wire conversion, lightning protection, power-down capability, and longitudinal performance which is independent of the battery-feed current magnitude.
Design of an Integrated Circuit for the T1C Low-Power Line Repeater
Describes a low-power T1C (3.152-Mbits/s) digital repeater which reduces the power requirements by a factor of approximately four compared to the previous version. The silicon integrated-circuit chip contains all the active circuitry necessary for one-way regeneration. The circuitry used for equalization, clock extraction, and regeneration are described in detail and the complementary bipolar (CBIC) technology is described in general terms.