Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!rutgers!netsys!vector!telecom-gateway From: cowan@marob.masa.com (John Cowan) Newsgroups: comp.dcom.telecom Subject: Re: Telecom in the news Message-ID: Date: 26 Jun 89 17:59:08 GMT Sender: news@vector.Dallas.TX.US Reply-To: John Cowan Organization: ESCC, New York City Lines: 23 Approved: telecom-request@vector.dallas.tx.us X-Submissions-To: telecom@eecs.nwu.edu X-Administrivia-To: telecom-request@vector.dallas.tx.us X-TELECOM-Digest: volume 9, issue 217, message 4 of 10 In article , wmartin@st-louis-emh2.army.mil (Will Martin) writes: >[There is also a sidebar item telling what a cordless phone is. I won't >bother typing that in; people here know that... :-) It does mention that >"modern cordless phones are equipped to use 10 channels ... Each channel has >a digital security code that can be programmed 256 different ways. The >result is a 2560-to-1 chance that two cordless phones with channels >programmed the same way will be within each other's broadcast range..." >That calculation of probability sounds a bit specious to me, but I'll leave >the rebuttal up to others for now... -WM] Utterly bogus. The "256 different ways" refers only to control signals; the security codes are designed to minimize the chance that the wrong base station will respond to a handset's keystrokes (or that the wrong handset will ring in response to a base's ring transmission). Two systems sharing the same channel and in an overlapping area will collide and allow eaves- dropping; however, if set to different security codes, the bases/handsets will ignore commands from the non-corresponding handset/base. -- John Cowan or UUCP mailers: ...!uunet!hombre!{marob,magpie}!cowan Fidonet (last resort): 1:107/711 Aiya elenion ancalima!