re do we need the clipper for cheap security from caronni nessie cs id ethz ch germano caronni in article aa pizzabox demon co uk gtoal gtoal com graham toal writes can someone tell me if hardware compression is or is not needed to run digital speech down k i think it is i ve heard it s not lets say bit samples would raw data at the corresponding sampling rate be usable if not how fancy does the compression need to be as far as i know isdn call it swissnet here and it s being plugged in it s bit hz gives you one channel of kbit sec i guess you should not go below a sampling rate of hz if you want to have same quality as on an analog line anybody knows compression algorithms factors for voice i ve posted some info on celp coding on sci crypt looks like you can squeeze speech into bps if you have a fast enough computer like a sparcstation or a newton with the acorn risc machine in it this drops the bandwidth to so low a figure that it s feasible to run speech over tcp ip running on top of slip down a v bis modem not only will this let us run point to point encrypted speech it ll let us run speech internationally over the internet if no one stops us by getting very heavy about regulations the thought of this if the administration realised would probably scare them shitless now of course the trick is to develop and define a standard protocol for internet speech damn fast allowing anyone who feels brave to inplement custom handheld hardware as well as us hacking it on our workstations shouldn t be too difficult the celp stuff is standardised we use tcp ip streams and a protocol allowing silences to be used to catch up on any net lag and also to avoid sending any data during silences ie it s not wise to be synchronised real time on each end because any net delays would add up to big voice lags as for me i m going to press ahead on trying this stuff as soon as i get my sparc back from being loaned out and buy the necessary microphone it ll save me a fortune in calling my friend in texas every night whether encrypted or not you know surely someone is working on this who it s so obvious why doesn t it exist already i ve only seen netphone for suns and it didn t do the celp compression so was restricted to ether connections g
