| ??? 12/02/08 18:23 Read: times |
#160517 - TelCo? Responding to: ???'s previous message |
I would start by looking at how the telephone company does this -- power + data on two lines. Data is sent over telephone lines for much more than 10km -- although the Tel.Co. probably uses amplifiers.
As to the data itself, there are 16 DTMF tones defined, and DTMF encoders and decoders have been around for a long time. Incidentally, I work with alarm systems, which have up to 999 different "points" or zones. When a message needs to be sent to a central station, the control panel connects to the phone line, dials a number, and waits for a response. When it gets the response, all the information is sent via DTMF tones. Upon receiving an acknowledgment the panel hangs up. This sounds a lot like what you want to do. --Rich |
| Topic | Author | Date |
| long distance communication | 01/01/70 00:00 | |
| TelCo? | 01/01/70 00:00 | |
| Contact ID? | 01/01/70 00:00 | |
| more information would be helpful | 01/01/70 00:00 | |
| Breif Explaination | 01/01/70 00:00 | |
| is there local power at the "field switches" ? | 01/01/70 00:00 | |
| INdustrial Data Comms Supplier | 01/01/70 00:00 | |
| In North America | 01/01/70 00:00 | |
| Another Industrial Data Comms Supplier | 01/01/70 00:00 | |
| Too brief | 01/01/70 00:00 | |
| re: | 01/01/70 00:00 | |
| Suggestion | 01/01/70 00:00 | |
| re:Andy Neil | 01/01/70 00:00 | |
| or with wifi | 01/01/70 00:00 | |
| Past Experience | 01/01/70 00:00 | |
| Serious warning | 01/01/70 00:00 | |
| with PLC or rs-485 | 01/01/70 00:00 | |
| SHM ,LHM | 01/01/70 00:00 | |
| It might interest you to know ... | 01/01/70 00:00 | |
| There are ways but, | 01/01/70 00:00 | |
| DC? ... over a 10 kM line? | 01/01/70 00:00 | |
| I might suggest that you consider... | 01/01/70 00:00 | |
HART | 01/01/70 00:00 |