Dear Ilan, Thanks for your response and we shall be in touch.
I hope I didnt confuse you with my use of the term handset. What I meant is the receiver part of the feature phone the part of the phone that contains only the microphone and earpiece and is lifted off the hook for speaking. To install the adjunct device, the receiver is disconnected from the base of the feature phone and the adjunct device is connected between them. Regards, David Drori Novarex Enterprises Ltd., PO Box 45178, Room 204, 2nd Floor, Park Center, Hamarpe 1, Har Hotsvim Industrial Area, Jerusalem 91450, Israel. Tel: +972 2 540 0168 Fax: +972 2 540 0169 GSM Cellular: +972 54 828011 E-mail: [email protected] -----Original Message----- From: Ilan Cohen [mailto:[email protected]] Sent: Tuesday, September 11, 2001 2:33 PM To: 'Novarex Enterprises Ltd.'; 'TREG' Subject: RE: Safety question regarding feature phone adjunct device Dear David The application need to be looked into more carefully. In general, your circuit could be defined as SELV or TNV2/3, or both. Since the handset may be considered TNV-3 than your power supply may be required to be a TNV-3 power supply and not a SELV power supply. Your USB is a SELV interface and should be insulated from TNV-3/2 circuits. Typical insulation is 1.5mm and 1000Vrms, yet it will be different if you look into other countries besides the US. You are invited to use our consulting and testing services. Ilan ---------------------------------------------------- Ilan Cohen Manager, Telecom Division I.T.L (PRODUCT TESTING) Ltd. 26 Hacharoshet St, POB 211, Or Yehuda, Israel. Tel 972-3-5339022, Fax 972-3-5339019 [email protected], website: http://www.itl.co.il <http://www.itl.co.il/> ---------------------------------------------------- -----Original Message----- From: [email protected] [mailto:[email protected]]On Behalf Of Novarex Enterprises Ltd. Sent: Tuesday, September 11, 2001 11:48 AM To: TREG Subject: Safety question regarding feature phone adjunct device Dear Treggers, We are involved in the development of an adjunct device that will be connected to a multitude of PABX proprietary feature phones from different manufacturers. The connections will be made through the narrow 4-pin socket connecting the handset to the base of the telephone. The add-on device will be connected to the handset itself. The add-on device will be powered from a low-voltage mains adaptor with relevant CE-mark and UL listing. The device will also be equipped with a USB connection to allow connection of a personal computer. Can anyone specify (quoting the relevant safety standard paragraph) the degree of safety isolation required between the portions of the device that are connected to the externally connected PC (that are referenced to PC ground), and the portions of the device that are connected to the four terminals of the handset socket on the feature phones? This isolation will govern the cost/complexity of magnetic and optical isolation components, and the type of relay used for restoring original operation of the feature phone in the event of a local power outage. It is due to the difficulty of ensuring adequate isolation between normally-open and normally-closed contacts of reasonably economical relays that I am asking this question. I am hoping that the requirement may be sufficiently low that we will not require expensive relay types for this application. Thanks in advance for all answers received. David Drori Novarex Enterprises Ltd., PO Box 45178, Room 204, 2nd Floor, Park Center, Hamarpe 1, Har Hotsvim Industrial Area, Jerusalem 91450, Israel. Tel: +972 2 540 0168 Fax: +972 2 540 0169 GSM Cellular: +972 54 828011 E-mail: [email protected]
