W.H. Grinsted: a forgotten hero [automatic telephony]
W.H. Grinsted: a forgotten hero [automatic telephony]
- Author(s): J.E. Flood
- DOI: 10.1049/ic:20010173
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- Author(s): J.E. Flood Source: 29th Annual Weekend Meeting History of Electrical Engineering, 2001 page ()
- Conference: 29th Annual Weekend Meeting History of Electrical Engineering
- DOI: 10.1049/ic:20010173
- Location: Chatham Maritime, UK
- Conference date: 29 June-1 July 2001
- Format: PDF
William Herbert Grinsted pioneered automatic telephony. He was responsible for improvements in relays, including: the knife-edge relay which became the standard telephone relay of the British Post Office (the BPO 3000 type), the isthmus armature used for impulsing relays, and the nickel-iron sleeved core to provide a high-inductance relay for use in transmission bridges. He also introduced the use of ballast lamps in transmission bridges to regulate line-feeding currents. He was responsible for the development of the Siemens No. 16 exchange system. This introduced, from Germany, gradings between switching stages and two-stage trunking of its preselectors (which was later adopted in crosssbar systems). His subsequent innovations included queueing systems for automanual switchboards and voice-frequency signalling systems. (9 pages)
Inspec keywords: biographies; telephone exchanges; relays; history; automatic telephone systems; electric current control
Subjects: Other general electrical engineering topics; Electronic switching systems and exchanges; Telephony; Current control; Relays and switches; Control of electric power systems
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