| ??? 10/17/07 17:43 Modified: 10/17/07 17:46 Read: times |
#145856 - Why is that the key?? Responding to: ???'s previous message |
However discribed, the current will always run in a loop, running back to the signal source.
If you want to point out a noteworthiness, then, that the loop has no connection to earth potential, and that the phone power is entirely separated from the households' mains voltage, so that you in the early days of telephony could call for help even when the mains voltage had a break-down. Kai |
| Topic | Author | Date |
| Telephone line voltages | 01/01/70 00:00 | |
| Beware! | 01/01/70 00:00 | |
| about that -48 volts ... | 01/01/70 00:00 | |
| i did, OUCH | 01/01/70 00:00 | |
| the key is to remember it\'s a current-loop | 01/01/70 00:00 | |
| The old stuff | 01/01/70 00:00 | |
| OK... YOUR grandparents ... MY parents ... | 01/01/70 00:00 | |
| Great Stuff ! | 01/01/70 00:00 | |
| Pulse dialing | 01/01/70 00:00 | |
| Not really surprising. | 01/01/70 00:00 | |
| Not necessarily | 01/01/70 00:00 | |
| Here, it detects both | 01/01/70 00:00 | |
| Pulse Dialling | 01/01/70 00:00 | |
| Current Loop | 01/01/70 00:00 | |
| Why is that the key?? | 01/01/70 00:00 | |
| It's the key to understanding it | 01/01/70 00:00 | |
| Sorry, but I cannot see the evidence | 01/01/70 00:00 | |
| Your circuit diagram shows it adequately | 01/01/70 00:00 | |
| What do you intend to build? | 01/01/70 00:00 | |
What I want to build | 01/01/70 00:00 |