Hi, It is not clear from the description of your product that this "industrial communication product" connects directly to a public telecom network. Mel's comments assume that it does while Rich Nute's assume that it doesn't. How far you are required to go depends on the answer to this question.
If your product does indirectly connect through some other third party hardware interface such that the third party hardware interface is what is seen by the public telecom network, then that interface would typically be subject to the telecom requirements, not your twisted pair port. WRT to the market value of having a card UL Recognized, I can say that as a system integrator, I would prefer to see all motherboards and expansion cards as Recognized Components. UL is constantly hounding me to control what cards we put in our base systems and I can not document or control the safety aspects of these 3rd party cards. It is highly impractical to control I/O circuits, fusing, board flammability, etc at an integrator's location. This causes problems during Follow-Up Service (FUS) inspections. If the Agencies need to have control of this stuff, then the obvious place to do it as at the card manufacturer's factory. If they can't get the card venors to do it, then they should drop the issue once and for all. Good luck. [email protected] ---------- From: mpedersen To: '[email protected]' Cc: 'emc-pstc' Subject: RE: PC card safety standards List-Post: [email protected] Date: Friday, May 30, 1997 8:43AM Hello Chris: 1) and 2): for the domestic market, your card does not yet need to = comply with UL 1950. I believe domestic requirements would be met by = designing to the requirements of UL 1459 (telephone equipment) and UL = 478 (computer equipment). A 1.5kV isolation transformer exceeds the UL = 1459 requirements for this barrier, so I believe you would be fine: = 1.0kV is all that is required. By the year 2000, however, all new = designs must comply with UL 1950, and by 2005, all products (old and = new) on the market must comply UL 1950. So, I would think that the = lifespan of your product would be the only consideration. I do not = believe that Joe blow computer shopper would know the difference between = UL 1950 or 1459, etc. All he looks for (maybe) is the UL mark. 3) and 4), Europe: Your product must be evaluated to EN 60950, the = applicable standard under the Low Voltage Directive for Information = Technology Equipment. With EN 60950 (and UL 1950, for that matter) a = 1.5kV dielectric barrier is what you will need for the telecom = interface, but that is not enough: there are certain construction = details (creepage, clearance, and distance through insulation) that you = must (generally) design to. In Europe, I believe (not 100% sure, I can check into that) it is safe = to assume that all computers on the market also comply with EN 60950. = There should be no "Hazardous Voltages" under normal and single fault = conditions in the computer. Also, there are two other directives that you must be aware of to sell = your card in Europe; the TTE (Telecom Terminal Equipment) directive, = and the EMC directive. It is necessary, in general, to demonstrate = compliance with these if you are going to apply CE marking to your = product to sell in Europe. Under the TTE directive, the major concern = is not to harm the network or interfere with the operation of the = telephone network, so, depending on your product, there may be some = additional safety criteria to meet under the TTE directive. The TTE = directive is not fully harmonized; what I mean by that, is that the = (FCC type signal power limitations, etc.) requirements for plugging into = the network still vary from country to country. There is headway being = made, however. If you wish, give me your fax number, and I can send you some = information on some (i don't know all) of the details you need to = concern yourself with in a situation like this. Good luck Chris. The above is solely the opinion of one who does not yet know all. Mel Pedersen Midcom, Inc. Homologations Engineer Phone: (605) 882-8535 [email protected] Fax: (605) 886-6752 ---------- From: = [email protected][SMTP:[email protected]] Sent: Thursday, May 29, 1997 2:41 PM To: [email protected] Subject: PC card safety standards Some Questions about PC & PC ISA card safety standards in both the USA = and=20 Europe. Background =20 I am responsible for a PC ISA card that is used to interface a PC to a=20 twisted pair industrial communications system. =20 The card is powered from the PC 12 Volts - no fuse. The twisted pair signal is transformer isolated and the signal is 5 Vpp. = =20 At present the transformer can take a 1500 VRM/1 minute hipot, however = it=20 does not meet IEC 950 construction requirements. We are presently modifying several designs to meet CE mark LVD = requirements=20 while we believe we understand and have dealt with the EMC requirements. = =20 This has resulted in the following Questions: 1) Is it a given that all PCs meet UL1950 or IEC 950 directly or=20 indirectly? I understand that family standard IEC1131 refers to IEC 950 = for safety. 2) Would my card need to meet UL1950 for the USA market? =20 If no - is there any perceived market value by meeting 1950 for this = card? 3) Would my card need to meet EN60950 (IEC 950) to satisfy the CE mark = LVD?=20 =20 I realize that the power and signal level are well below the required=20 levels to be considered by the LVD however if considered as part of the = PC=20 then it is not so clear. 4) Is there a market expectation to see EN60950 on a PC card in Europe? By now I imagine you all get the intent of my questions. =20 If there is anything else you feel is important to consider "safety = wise"=20 on the topic of PC cards,=20 I would very much appreciate it Regards Chris Wells Sr Des. Eng. Cutler-Hammer [email protected]
