Weighing scale
The balance (also balance scale, beam balance and laboratory balance) was the first mass measuring instrument invented. In its traditional form, it consists of a pivoted horizontal lever with arms of equal lengththe beamand a weighing pan suspended from each arm (hence the plural name ""scales" for a weighing instrument). The unknown mass is placed in one pan and standard masses are added to the other pan until the beam is as close to equilibrium as possible. In precision balances, a more accurate determination of the mass is given by the position of a sliding mass moved along a graduated scale. Technically, a balance compares weight rather than mass, but, in a given gravitational field (such as Earth's gravity), the weight of an object is proportional to its mass, so the standard masses used with balances are usually labeled in units of mass (e.g. g or kg).
Digital Multiplex System
Exploratory development on the technology began at Northern Telecom's Bell Northern Research Labs (Ottawa, Ontario) in 1971. The first Class 5 switch, the DMS-10, began service on 21 October 1977 in Fort White, Florida and the first toll switch (Class 4), the DMS-200, entered service in 1979 in Ottawa, Ontario. The DMS-10 was the first commercially successful Class 5 digital switch in the North American market and had a profound impact on the industry. Of the numerous digital switching products introduced in the North American telephone market in the late 1970s, only the Nortel DMS family is still in production. GENBAND acquired Nortel CVAS assets including the DMS line in 2011 and rolled it into its IP-based GENiUS platform. The GENiUS-750nt is the first product to include adaptive nano-tech compression and resynchronization modules from Ericsson, to replace the digital cross-connect (DCS) in place since the earliest DMS releases.