| ??? 07/11/05 07:59 Read: times |
#96978 - tester Responding to: ???'s previous message |
Oh, so this is a sort of a tester, used in field to find wiring errors?
Then it maybe does not deserve the "heavy" protection, but certainly worth a couple of zeners or transils. Then, I wouldn't rely on earth connection between local earth and office earth. Rather, I would add something which "measures" the polarity of voltage difference between the lines - this gives you the line reversal and also short+disconnect (you could not distinguish between these two, but that possibly might be left to the line-to-earth measurement). Beware, I know little on phones, so this is just a rough guess, treat it as so. Jan Waclawek |
| Topic | Author | Date |
| First:Wiring Error Detection! | 01/01/70 00:00 | |
| It depends | 01/01/70 00:00 | |
| First observation | 01/01/70 00:00 | |
| First observation | 01/01/70 00:00 | |
| Danger of surges | 01/01/70 00:00 | |
| Sort of. | 01/01/70 00:00 | |
| Sort of | 01/01/70 00:00 | |
| Re: Sort of... | 01/01/70 00:00 | |
| Phone line transients | 01/01/70 00:00 | |
| Schematic of a simple filter | 01/01/70 00:00 | |
| Research... | 01/01/70 00:00 | |
| router | 01/01/70 00:00 | |
| gas discharge tubes | 01/01/70 00:00 | |
| GDT | 01/01/70 00:00 | |
| Gas discharge tubes | 01/01/70 00:00 | |
| Oh dear... | 01/01/70 00:00 | |
| Gas Tubes | 01/01/70 00:00 | |
| Or | 01/01/70 00:00 | |
| Ring. | 01/01/70 00:00 | |
| Where's Ring? | 01/01/70 00:00 | |
| I say .. | 01/01/70 00:00 | |
| Telephone systems | 01/01/70 00:00 | |
| Telephone systems | 01/01/70 00:00 | |
| tester | 01/01/70 00:00 | |
| Yep Jan! | 01/01/70 00:00 | |
| Even for testing not allowed | 01/01/70 00:00 | |
| Line simulator | 01/01/70 00:00 | |
| Another Misunderstanding Kai | 01/01/70 00:00 | |
| misunderstanding | 01/01/70 00:00 | |
| Jan | 01/01/70 00:00 | |
| Confusion... | 01/01/70 00:00 | |
| quote from my previous post | 01/01/70 00:00 | |
| It's a current loop ... | 01/01/70 00:00 | |
| Correction | 01/01/70 00:00 | |
| ring? | 01/01/70 00:00 | |
| Yes Jan! | 01/01/70 00:00 | |
| Agreed | 01/01/70 00:00 | |
| it explains a few things, though | 01/01/70 00:00 | |
| Phone Line Ground | 01/01/70 00:00 | |
| Not quite offtopic... | 01/01/70 00:00 | |
| Alternative schematic | 01/01/70 00:00 | |
| Just a simple comparsion !!!!!!!!!!!!!!! | 01/01/70 00:00 | |
please help me (telepone) | 01/01/70 00:00 |