The Transistorized A5 Channel Bank for Broadband Systems

This paper discusses in broad terms the design of a radically new family of multiplex terminals, designated the L multiplex, designed to work with any of several broadband transmission facilities. The relevant historical background of multiplex terminals is covered and design objectives for the new equipment are outlined. The new multiplex takes advantage of advances in the state of the art to reduce the size of equipment and increase reliability, while it retains the proven advantages of older equipment. Other advantages of the new multiplex include in‐service maintenance, decentralized carrier supplies, and increased flexibility. The latter permits its use with as few as 60 or as many as 1860 voice channels and also adapts it for use with wideband data service. Compatibility with older multiplex equipment was maintained where possible, but in order to meet future demands for broadband service, it was decided to modify older equipment rather than compromise the design of the new to maintain compatibility.

The New L Multiplex - System Description and Design Objectives

Hallenbeck¹,

Mahoney²

1963

New Group and Supergroup Terminals for L Multiplex

Graham¹,

Adams²,

Powers³

et al. 1963

L multiplex terminals provide the several stages of modulation required to translate telephone channels into the broad basebands which can be transmitted. on long‐haul systems. The group and supergroup equipment has been redesigned incorporating many new features. Pilot‐controlled regulators are provided to improve performance. Plug‐in modules and automated monitoring facilitate maintenance. The equipment is arranged to reduce office cabling and installation cost. By the use of transistors and other newly developed devices and components, a size reduction of 10 to 1 has been achieved and the required power greatly reduced.

Carrier Supplies for L-Type Multiplex

Walter¹,

Evans²,

Ginty³

et al. 1963

This article describes the carrier and pilot supply equipment of the Ltype multiplex. Also discussed is the modernized carrier supply for the A-type channel banks described in an earlier paper.A short review of previous carrier equipment and recent developments in carrier application is followed by a general discussion of the design approach. Finally, specific circuits and equipment units are described.