Hello Eric and all: Certainly clause 6 of EN 60950 would apply. The ISDN-U interface could be considered TNV-1, or possibly TNV-3 if you are above 60VDC and below 120VDC. For TNV-1, at least 1.0kV of isolation would be required between the network and other user accessible ports or circuitry, and 1.5kV of isolation would be required between the user and handheld parts. This is in clause 6.4.1 and 6.2.1.2 of EN 60950.
For TNV-3, at least BASIC INSULATION is required. The working voltage for this barrier is generally considered to be 150VDC. Also, for Norway and Sweden, they will require SUPPLEMENTARY INSULATION rated at mains voltage to protect the network from poor grounding. The reason (at least as far as I understand) that the U-interface has not been as well defined as the S/T interface is that the U-interface has not been accessible to the user in Europe. I have heard that some day it will be, but I don't know when if it ever will be. Any new news on this anyone? Can't help with EMC - hope the above helps. Mel Pedersen Midcom, Inc. Homologations Engineer Phone: (605) 882-8535 [email protected] Fax: (605) 882-8633 Midcom or myself will not take any responsibilities for blunders made as a result of the above statements. ---------- From: [email protected][SMTP:[email protected]] Sent: Monday, August 03, 1998 9:04 AM To: [email protected] Subject: Re: ADSL modem - safety & EMC This subject is somewhat timely for a project I'm dealing with now; an ISDN S/T and U interface tester. The S/T port for end-user access is well defined. However, based on the feedback I get from our designers, the U interface has no firm electrical spec, making it hard to determine with certainty the isolation/insulation requirements. We're doing our own safety tests under the supervision of a TUV engineer. I find the lack of a specification for the U interface - hard to fathom. Eric Lifsey Compliance Engineer/Manager National Instruments "Victor L. Boersma" <[email protected]> on 08/02/98 05:03:03 PM Please respond to [email protected] To: "INTERNET:[email protected]" <[email protected]> cc: (bcc: Eric Lifsey/AUS/NIC) Subject: ADSL modem - safety & EMC > I'm into a new project: an ADSL board, installed in the CO and connected to > ISDN lines. There is an ETSI document that gives all ISDN interfaces (in Europe) and what safety requirements out of EN 60950 apply at each interface. Only thing I am not sure of after all those years (ISDN is a bit of an old technology) is whether it addresses interfaces inside the Central Office. It was intended to cover interfaces at the Customer Premises, as I recall. Sorry but don't have the number of that document any longer. In any event, safety and EMC standards are not concerned with technologies, so if you apply 60950, you should be alright as long as you know what to expects at the interfaces that you work. E.g., does your modem sit behind the CO carbon protectors and heatcoils ? Do you know what degree of isolation/protection from lightning and overvoltages those provide in the types of Central Offices that you will deploying your devices ?? I may be proven wrong, but I doubt that you can get that info at any WEBsite. I also doubt that you will get a uniform pan-European answer. I suggest that you go back to your marketing people and ask them what their target markets are before going on a wild goose chase. Ciao, Vic
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