Published 9 Dec 2018
Telephone manuals, schematics etc
I collect old telephones as they are useful as a source of parts. Their service manuals often contain parts specifications or schematics which help to identify components.
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Overview
Business phones, mainly internet IP phones these days, often contain character or graphic LCDs. Earlier phones contain larger components, with larger, more widely spaced connectors, and so are often easier to salvage, test and re-use. The trend is to use micro connectors with 0.5mm or less pin spacing which are very problematic unless you obtain a suitable breakout board with easier to access connections. Some phones have displays only capable of displaying symbols and digits, some have full alpha-numeric characters, and some have a mixture of all three.
The latest phones (both cellphones and desktop phones) are mainly using graphic dot-matrix LCD displays, some in fully colour.
On the sidebar there is a list of telephones that have passed my way.