On 4/10/2008, Ron Pickard wrote:
I have to disagree. My disagreement is based on the scope of ANSI/TIA-968-A found in clause 1.1. From the Scope’s opening paragraph: “This standard specifies technical criteria for terminal equipment approved in accordance with 47 CFR 68 for direct connection to the public switched telephone network, including private line services provided over wireline facilities owned by providers of wireline telecommunications. These technical criteria are intended to protect the telephone network from the harms defined in 47 CFR 68.3.” The emphasis is mine, but it clearly makes Part 68 applicable only to equipment with a direct connection to the PSTN. Remember, Part 68’s intent is to protect the PSTN from harm as is also stated in the scope. Therefore, Part 68’s requirements should not apply to VoIP phones if they don’t directly connect to the PSTN. Hi Ron: I agree with your conclusion, but I think the justification is a bit different >from what you describe. While the original intent of FCC Part 68 was limited to protecting the network >from harm, the requirements for HAC (Hearing Aid Compatibility) were added back around 1980 in response to a political effort. HAC and the related, newer requirements for a volume control are the only requirements within FCC Part 68 that are not harms-based (some would argue that the Type B lightning surge is not harms based, but that gets into the murky area of defining what constitutes "harm" to the network). Several years ago the Federal Government attempted to divest itself of from maintaining and administering FCC Part 68 by turning those tasks over to an industry group. This led to the creation of ACTA and TIA-968. The combination of ACTA and TIA-968 pick up about 90% of the technical and administrative requirements that were formally handled directly by the Federal Government. However, due to the fact that HAC was a legal requirement voted by Congress, that portion of FCC Part 68 was retained in the new, slimmed down version of FCC Part 68. So, HAC remains a Federal requirement called out in clause 68.4 of FCC part 68, as quoted by Bret. It is not within the scope of TIA-968. That being said, my interpretation of clause 68.2 of FCC part 68 is that it limits Part 68, including the HAC requirements, to equipment that is *directly* connected to the public switched telephone network. In my view, a SIP phone with an Ethernet jack does not directly connect to the PSTN. This is just my own interpretation of the law, and I stand ready to be corrected if there is a legal precedent that has been established that somehow expands the scope of Part 68 to cover VOIP phones. I should note that ensuring the HAC compatibility of a phone usually involves only the simple choice of using a handset receive transducer that was designed to produce the required magnetic field. These receivers are typically not much more expensive than non-HAC versions developed for use in countries other than the USA. Of course, documenting compliance involves the added expense of performing the HAC test, but that is not usually a big expense. So, if a manufacturer wants to be conservative and make their VOIP phone HAC compliant, it generally not difficult or expensive to do so. Joe Randolph Telecom Design Consultant Randolph Telecom, Inc. 781-721-2848 (USA) [email protected] http://www.randolph-telecom.com <http://www.randolph-telecom.com/> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to [email protected] Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas [email protected] Mike Cantwell [email protected] For policy questions, send mail to: Jim Bacher: [email protected] David Heald: [email protected] All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
