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| Thread ID: 117831 | 2011-05-06 14:07:00 | Phone line polarity tester | Agent_24 (57) | PC World Chat |
| Post ID | Timestamp | Content | User | ||
| 1199956 | 2011-05-09 10:43:00 | Doesn't every device using the phone line require a telepermit sticker in order to be sold in NZ? | Greven (91) | ||
| 1199957 | 2011-05-09 10:48:00 | Doesn't every device using the phone line require a telepermit sticker in order to be sold in NZ? New Zealand law states that "a person may only connect equipment to a network or anything connected to a network that is owned or operated by an operator who has agreed to the connection" (section 106, Telecommunications Act 2001). Telecom's agreement to the connection of any equipment is shown by Telecom issuing a Telepermit. Once equipment has complied with the specifications and conditions in accordance with the PTC Acceptance Testing Process, Telecom provides an agreement for connection of the equipment by granting a Telepermit to the applicant. The Telepermit certification illustrates that the equipment is fit for purpose, that it meets requirements and it can be expected that it will not interfere with other services or users. Products sold in New Zealand that have been granted a Telepermit also have the right to display a Telepermit label on the equipment. This label clearly indicates that the product has been certified and may be connected to the Telecom network. Source:www.telepermit.co.nz |
somebody (208) | ||
| 1199958 | 2011-05-09 10:52:00 | Doesn't every device using the phone line require a telepermit sticker in order to be sold in NZ? As far as I'm aware. But then there is so much that people buy from sources overseas that may not have been tested. I have not seen any without the telepermit but that does not mean there are none here does it? |
Snorkbox (15764) | ||
| 1199959 | 2011-05-09 11:00:00 | So to answer your question, Agent 24, polarity can be important for many circuits and polarity has been important for many years. I do not doubt that it is important, my real question was if a wrong polarity issue was prevalent here as much as in Australia as Silicon Chip seems to think it is. Did the Silicon Chip article have any background to the "polarity problem" with ADSL modems? The Aus Standard for ADSL Customer equipment contains the following "Line polarity CE operation shall be independent of line conductor polarity. " They said in the article that not all modems were affected but "some" were. Perhaps it is only older ones. I just might build the device for fun, it's only Four LEDs (2 Red, 2 Green), Two 12k resistors and an RJ12 jack. (shouldn't be hard to figure out how it works!) |
Agent_24 (57) | ||
| 1199960 | 2011-05-09 15:19:00 | This is all assumptive of a DC-run phone system, no? I just took my DVM to the twisted pair in my system and it's obviously AC of a few different frequencies. The frequencies is where the system can differentiate from a 80V 30Hz RING verses a 18V 800Hz TALK signal and this seems so much more logical to me. At least this is how the voltages and freqs show up on my scope-meter. Can anyone tell me if NZ actually has a GROUND dedicated supplier line in their homes from their pole drop or do any of your locales still use the single-line-to-EARTH domestic electrical supply? This might be why you are still using DC for your communications systems. IIRC - DC gets 'lost' at long distance in small wiring whereas AC has a lower loss rate - right? |
SurferJoe46 (51) | ||
| 1199961 | 2011-05-09 20:54:00 | If you've still got an 80v ring the line is still a traditional analogue type. 800Hz would be right in the voice band so I couldn't see it being used to power anything. Are you sure that you don't see the usual 48v dc? Domestic mains power is a phase and a neutral from the pole with the neutral linked to a ground stake at the switchboard. |
PaulD (232) | ||
| 1199962 | 2011-05-09 21:10:00 | Paul - I think our phone system is using some oddball floating grounds and power supplies these days as they have trouble with twisted pairs carrying as much information as they actually need and start jacking the ground base and the voltage peak to match at different plateaus. With the advent of FIOS and the newer cable systems taking some of the thunder from the twisted pairs and rightly so - there is/are a lot of variable voltages in the system nowadays. So far I haven't 'seen' 48 volts unless it is just not a constant ON and it only appears at certain times in the line's use. |
SurferJoe46 (51) | ||
| 1199963 | 2011-05-10 11:18:00 | Joe, many USA phone lines have a test unit fitted to the end which can be detected by the central office. These test units (there are different brands) can sometimes mask the 50 volts that would normally appear across the phone pair, but one thing is compulsory - put an off-hook phone across the line and you must be able to draw dial-tone. | decibel (11645) | ||
| 1199964 | 2011-05-10 14:58:00 | Interesting - I know the phone company wants us to only use FCC-Ringer Equivalency qualified gear on our end - maybe that test unit is to keep the consumer from loading the system down. At one time we were limited to four extra phones in any single pair line since they didn't like supplying amperage enough to heat our houses or run our lights. |
SurferJoe46 (51) | ||
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