| ??? 07/10/05 03:57 Modified: 07/10/05 04:16 Read: times |
#96938 - First:Wiring Error Detection! |
Most of you know that:
When your telephone is in on-hook state the "TIP" is at about 0v, while "RING" is about -48v with respect to earth ground. When you go off hook, and current is drawn, TIP goes negative and RING goes positive (I mean less negative). A typical off hook condition is TIP at about -20v and ring at about -28v. This means that there is about 8V voltage between the wires going to telephone in normal operation condition. Now i need to a circuit with 3 possibilities 1.Short circuit Detection, 2.Open circuit Detection, 3.Normal Operation, For this reason i suggest a circuit with 2 transistors So if LED1 and LED2 were off short circuit is occurred and if both of them were on normal situation is happened anf if only lED 2 is on open circuit is happened 
Is my approach is the best,Or it has a better solution,Not special chip I am waiting for you reply Thanks beforehand Mehdi |
| 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 |