in my decades of being interested in power metering this is the only model i have ever seen going so far back before digital meters that did AMR
i found this writing on the internet
there is a reference online that GE patented the AMRAC system April 9, 1964
National concern for energy conservation and the increasing cost of electric generating capacity are accelerating interest in load-management systems having the potential to influence daily load profiles. Load-management functions can best be performed by a centrally controlled system. Just as central control of the load management system by outward communication is advantageous, central collection of data by inward communication also adds value. If central control and two-way communication are to be used, some means of communication must be provided between the central location and each end user. General Electric's Automatic Meter Reading and Control (AMRAC) system uses distribution line carrier because it is economical and information can be transmitted in both directions. A small version of this rudimentary meter-reading system, known as AMRAC Phase I, was installed on line for Philadelphia Electric in late 1974 and 1975 to test the encoder and communication. By mid-1976 the next generation of AMRAC equipment became available. Units were installed and operating on six utility systems before the end of that year. The success of Phases I and II has now fostered the demand for commercial production of the equipment. General Electric is in the process of implementing a Phase III AMR-AC system. (MCW)
2. HISTORY OF AMR
AMR was first tested about 40 years ago when AT&T conducted trials in cooperation with a group
of utilities and Westinghouse. After those successful experiments, AT&T offered to provide phone-based
AMR services at $2 per meter. The price was four times more than the monthly cost of a person to read the
meter. Thus, the program was considered economically unfeasible. However, in 1972, the General Electric
Corporate Research Center, in conjunction with GE Meter Department in Somersworth, New Hampshire,
began an R&D effort for a remote meter reading system for centralized TOU (Time-Of-Use) metering called
AMRAC. Meanwhile, at Rockwell International, a Utility Communication Division had been founded in
1977 to develop distribution carrier communication systems. In the fall of 1984, General Electric acquired
from Rockwell International an exclusive license to commercialize their distribution line carrier product
designs, related research and technology. The modern era of AMR began in 1985, when several major fullscale projects were implemented. Hackensack Water Co. and Equitable Gas Co. were the first to commit to
full-scale implementation of AMR on water and gas meters respectively. In 1986, Minnegasco initiated a
450,000-point radio-based AMR system. In 1987, Philadelphia Electric Co, faced with a large number of
inaccessible meters, installed thousands of distribution line carrier AMR units to solve this problem.[3]
Advances in solid-state electronics, microprocessor components and low-cost surface-mount technology
assembly techniques have naturally been the catalyst to produce reliable cost-effective products capable of
providing the economic and human benefits that justify the use of AMR systems on a large-scale basis.