Other biometric technologies not specified here include ear recognition, signature dynamics, key stroke dynamics, vein pattern recognition, retinal scan, body odour recognition, and DNA recognition. These are technologies which are either in early stages of development or used in highly specialised and limited contexts.
TEXTBLOCK 1/1 // URL: http://world-information.org/wio/infostructure/100437611729/100438658399
The Roman smoke signals network consisted of towers within visible range of each other and had a total length of about 4500 kilometers. It was used for military signaling.
For a similar telegraph network in ancient Greece see