🚀 go-pugleaf

lcmyu@crypto2.uwaterloo.ca (Luis Ola Toshio Chi-Ming) writes:
>In article <1992Nov9.181433.12025@shearson.com> pmetzger@snark.shearson.com (Perry E. Metzger) writes:
>>Its all really easy. CELP compression can be done with cheap DSPs --
>>you can buy the code if you don't feel like writing it yourself. The
>>encryption can be done an order of magnitude faster than you need even
>>on conventional processors.  V.32bis modem modules are a dime a dozen.
>>You don't need to be AT&T to do this -- any talented EE with a few
>>weeks of work could put a system to do this together.
>
>Can someone tell me how these digitally encrypted phones provide
>reasonable security in light of the following problem.  Phones lines
>can tolerate raw data rates of 9.6 kbps whereas voice requires 
>64 kbps.  Let's say the CELP compression reduces the voice
>requirement down to 9.6 kbps (voice becomes noticibly choppy thereafter).
>Where do they allocate the bandwidth needed for sycronization and error
>correction.

CELP produces very good voice at 4800 bits/second. V.32bis does
14kbits/sec very reliably. Does this answer you questions?

--
Perry Metzger		pmetzger@shearson.com
--
"They can have my RSA key when they pry it from my cold dead fingers."
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