A couple of comments: -As Randy and Jim Brunssen will recall, an exhaustive comparison of UL 950 and 1459 took place under TR 41.7.1 For those who still have the paperwork, reams of rationale still abound. This comparison, and the harmonization of UL 1459 and CSA Standard C22.2 No. 225, were the first steps in the harmonisation with IEC 950(now 60950), UL 1950 and C22.2 No. 950. -We in Canada did not have the advantage of Bellcore specs. We therefore had to rely on the Canadian equivalent of 1459, C22.2 No 225, to specify what we wanted in the way of safety. Thus, when Bell Canada no longer was able to look on Nortel Networks as a private in-house supplier who designed to our requirements, (and also began buying from other sources), the only way to specify safety was by referencing CSA standards in purchase specs. 225 was it. -The question of what forms a telecom network is one that borders on philosophy, rather than being technical. 'Network' equipment on customer premises, such as remotes, is clearly included; some would include the telephone set as well. The question of jurisdiction, not technical requirements, limit 60950/1950/950 to a subscriber's installation. -Meeting these standards should not be a surprise to suppliers who sold in Canada. The documents were made fully usable for network equipment, because only network equipment used by certain carriers is exempt from listing/certification and inspection. In Canada, for those seeking network equipment certification, it was the only show in town. Probably in the US as well. -As stated, the main difference between the international standards, which came primarily from the IT industry, and the Telecom standards, was the measurement of clearances/creepages as opposed to checking for the functional equivalent through dielectric tests. But when the various groups set out to harmonize internationally, it was spelled out that 1459, with this different approach, was going to be withdrawn. The writing was on the wall that something would have to change. -As for the question of the higher voltages, the separation of 'raw ringing' (the old slip-ring ringing generators are long gone), and trippable ringing by a 'ring-trip relay' or its modern equivalent was the subject of much debate. This question applies as well to the ringing generated in a PBX. -Other high voltages do exist in telecom equipment, as Jim Weiss stated, and are used to power other equipment. These voltages cannot be considered as other than hazardous, and should therefore not be accessible in a user access area.
As for where that leaves suppliers faced with the withdrawal of 1459, surely, if some suppliers have not prepared for this change, the solution would be a postponement of the DOW of 1459, not its re-establishment (which would require updates, etc., and hamper international trade). Regards, Frank McCaughey
