---------- Original message from David Drori ---------- > Dear Treggers, > > I have observed that data modem cards for the UK market, designed for > installation in PCs, have an insulating cover surrounding the TNV > (Telecommunications Network Voltage) areas of the circuit. I have also seen > this requirement stated by one of the modem chip manufacturers in its > applications literature. However, I am not at all sure whether this practice > is universal. > > Can anyone tell me if the insulating cover is a requirement, and if so, where > it is stipulated? Alternatively, can anyone state categorically that data > modem boards are being sold (with BABT approval, of course) without a > protective cover? > > Thanks in advance to all those who respond. > > Best regards, > > David Drori > > --------------------------------------------------------------------------- > ------------------ Novarex Enterprises Ltd., POB 2833, Jerusalem 91028, > Israel. Tel: +972 2 581 0995 Fax: +972 2 581 3750 Mobile: +972 5 067 8686 > E-mail: [email protected] > --------------------------------------------------------------------------- > ------------------ >
David This requirement comes from BABT Application Note 48 'Recommendations For Terminal Equipment For Use Inside A Host Equipment', which covers safety aspects of host independent apparatus. The three areas it addresses are: - The power required by the combination of equipment could exceed the rating of the host supply. - The environment provided by the unknown host could contain hazards. This does not necessarily mean that the host itself is unsafe but installation of the telecommunications equipment within the host could compromise a safety barrier or result in hazardous voltages being too close to network circuitry. - Some types of telecommunications networks use voltages which exceed the SELV limits and must be insulated from unearthed operator-accessible conductive parts. In the latest issue of ApN 48 (Issue 5) there is a route around having to provide covers, however it introduces a lot of additional labelling/user-guide requirements. Regards Ben ------------------------------ Ben Wrigley Approvals Specialist KTL Newlands Science Park Inglemire Lane Hull HU6 7TQ UK Phone: +44 (0)1482 801801 Fax: +44 (0)1482 801806 Web: http://www.ktl.co.uk Email: [email protected]
