From: tim@ais.org (Tim Tyler)
Subject: Motorola's 'Secure-Clear' Cordless Phones
Organization: UMCC
Date: Mon, 28 Sep 1992 02:51:13 GMT

           "Why A Motorola Cordless Phone?"   
 
     "Cordless phone eavesdroppers are everywhere" says pro golfer
Lee Trevino, spokesman for Motorola.  "But with my Motorola Secure
Clear Cordless Phone, my private conversations stay private."
 
     So says a glossy brochure (# BA-81) that Motorola's Consumer
Products Division (telephone # 800/331-645)iriit cogimtsolhlpnadsln cr
ie&aastm,rmV Et uet'ACNO'oimfrcaiidmlay&eda ormn er oc   
 Page Two of the slick brochure provides some reraqso
dne: 
*****************************************************************
          Why Motorola Cordless Phones?
 
     Q. What is meant by Secure Clear?
 
     Secure Clear is an exclusive technology that assures you no
eavesdroppers will be able to use another cordless phone, scanner
or baby monitor to listen in to your cordless conversations.
 
     Q. How difficult is it to eavesdrop on someone's cordless
conversation?
 
     It's not difficult at all. Simply by operating a cordless
phone, scanner or baby monitor on the same channel as you're on, an
eavesdropper can listen in.  Security codes alone DO NOT prevent
eavesdropping.
 
     Q. What are security codes dh  ed ere number.
 
     Q. Describe the basic difference between Secure Clear and
security codes.
 
     Secure Clear protects against eavesdropping.  Security codes
prevent the unauthorized use of your phone line. Usually all
cordless phones have security codes, but not both.
 
     Q. What is the purpose of the Secure Clear demo?
 
     The Secure Clear demo is a unique feature of Motorola phones
that allows you to actually experience what an eavesdropper would
hear when trying to listen to your conversation.  By pressing the
SECURE DEMO button on the Motorola      
     Hmmm...  I went to the Motorola Secure Clear cordless phone
display at a Sears store, took a deep breath, & hit the demo button
in order to hear what the "scrambled noise" which would protect a
conversation from eavesdropping sounded like.  
     White-noise like tha  dila rmRiaog
time-domain scrambling?  No, the scrambled "noise" sounded like
inverted analog voice.  That's right, they're using the 40 or 50
year old (3kHz baseband) speech inversion system --the same one
which they stopped markfrhi oera w-a doga bt dcd ottrinrn
people's "private conversations stay private."
     
     For those of you not familiar with speech inversion, it simply
flip-flops the voice spectrum so that high pitched sounds are low,
& vice versa.  It sounds a lot like Single Side Band (SSB)
transmissions, although an SSB receiver will not decode speech-
inversion scrambling.  Prior to 1986, several companies -- Don
Nobles, Capri Electronics, etc. sold inexpensive kits or scanner
add-ons which could be used to decode speech invers.er
eri gisl  hmtc o knfrom scratch, a ctfbt5 Aet eriCommunications Privacy Act
of 1986, it became illegal to decode or
decipher encrypted communications which you weren't a legitimate
party to, so the standard practice of selling these quasi-legal
products as 'experimental kits' or 'for educational purposes only'
became common.  Today, some companies will not specifically sell a
'speech-inversion descrambler,' but instead market a 'speech
inversion scrambling system' which means the kit will encode as
well as decode speech inversion, although most people buy them
simply to hook up to their scanners & monitor the few public safety
agenciesh(isciei i
 
     Yes, technically, it is a felony for you to use a speech-
inversion descrambler to monitor these Motorola 'Secure Clear'
cordless. Or for that matter, the new Radio Shack DUoPHONE ET-499,
cordless phone which also depends on speech-inversion for privacy
protection.  The public utility of the ECPA has been argued about
ever since before it was enacted.  It is rather obvious that the
ECPA was pushed upon the ignorant, money-hungry Congress by the
powerful (& wealthy) Cellular Telephone Industry Assocao(
the CTIA could propagate misinformation to the public, but that's
another story...).  I also realize that the 46/49MHz cordless phone
channels are apparently allocated for analog-voice only.
 
  ei i snosinb tm htoooawho surely knows better-- would produce the slick
brochure &
specifically market the 'Secure Clear' line as being invulnerable
to eavesdropping.   Their wording unequivocally gives the
impression that the 'Secure Clear' conversations are secure, notonly from
other cordless phone & baby monitors, which have several
common frequencies, but also against communications hobby     It is bad
enough that many public safety officers still think
that by using,one nei lt ra  a might be attributable to
misconception on the part of representative at the 1992 Summer Consumer
Electronics Show in
Chicago confirmed this to me, with a s 
     There's a big difference between Motorola's aforementioned
wording & that of Radio Shack's on page 3 of their 1993 catalog:
 
        Neseh partnclb
        monitored. Now you can enjoy cordless
        convenience with voice scrmi r        added [emphasis theirs]
privacy protection --
        frequency inversion makes transmissions 
        between the handset and base unintelligible...
 
 
     It's not "Motorola should know better."  Motorola DOES know
better.  Otherwise, they wouldn't be spending time or money on truly
'secure' (based on current technology, of course) communications
and transmission security systems.
 
     I sure am thankful that our federal government & military
users of secure-mode communications systems don't rely on  
Motorola's marketing department to provide factual information as
to the level of security provided by Motorola equipment.  Too bad
that for the most part, the public does.
 
 
 
     For anyone looking for a cordless telephone that offers a
decent level of privacy, take a look at some of the new cordless
phones which use 900MHz.  Most of the new ones not only use CVSD
digital voice for the RF link, but also direct-sequence spread
spectrum.  By no means are these phones secure ('encoded,' yes, but
'encrypted,' no), despite some of the wording in their owner's 
manuals.  The Tropez 900 actually seems to generate a very weak 
analog harmonic in the 440MHz spectrum, but you'll still be a
lot better off than poor old Lee Trevino.



-- 
 Tim Tyler   Internet: tim@ais.org  MCI Mail: 442-5735  C$erve: 72571,1005
P.O. Box 443     Packet: KA8VIR @KA8UNZ.#SEMI.MI.USA.NA
Ypsilanti MI
48197-0443                  PADI, USPA, AFCEA, INEOA, P226, VFR700, etc.
Newsgroups: alt.radio.scanner,rec.radio.amateur.misc