I use a fax machine as a printer, very neat use of a laptop's fax/ modem card.
I have a simple line simulator with 18V battery supply. But sometimes the fax machines (especially old ones) fail to answer manual fax sent from the PC. That is when the Manual Answer is not available of defunct.
Is there a simple circuit to use the tel.-companie's Ring Tne to make the fax wake up and start receving?
Idealy i look for a simple circuit that passes the ring signal to the fax , but does not allow the line to trip to off-hook. ( i.e. avoid being charged).
My line simulator is essentially 2 caps of 1uF for ac coupling, and two 9v batteries across the two telephone wires (see
formatting link
)
In my area ring signal is 25Hz 60Vac rms. but a universal solution for ring signal of 20Hz 80Vac would be nice.
thanx for your input and for the techlib reference uncle... , it gave some new ideas.
But my point is to use the telephone companies ringer, for example I call the fax number from my mobile to wake up the fax. If i were to use a dedicated ringer, it might not be compatible with different countries I visit. On the other hand where there is a fax machine there is always a telephone line, to get a ring signal from. what's more the telephone company provides compatible ring for the local fax.
The setup i need is not permenantly attached to the line, just when i want to print or (dirty)scan something on the go. And btw If i were to install all the printer drivers for printing and scanning just to print a couple of pages on the go, well it doen't worth it. Fax quality sufices most of the time for me.
I give below the simple circuit i think I need, i hope it shows correctly, in courrier font... What kind of Cx capacitors I need?
+---------+---o +9V | | \ \ 1k / / 1k \ \ | 1uF | T-connect o---.---| |---.----------------.---------------o PC Fax/Modem1 | FAX o---.---| |---.----------------|-------.-------o | 1uF | | | \ \ | | 1k / / 1k - - \ \ - Cx - Cx | | | | +---------+---o -9V o o TELEPHONE LINE, for ring signal
Notes:
1uf 100V non-electrolytic
1K resistors 1watt
The nice thing about this possible set up is light (for traveling), inexpensive, and safe (please ?)
On the point of the fax not answering the icoming call: I see on other discussion
Telephone exchange off-hook detection question on-hook: no DC current, -48V line voltage off-hook: min. 20 mA DC current and 5-12 V line voltage
those conditions are true in US/UK/Europe?
does that mean that in the absence of DC current, the line rings but even when the fax wakes up, the line still keeps ringing (no toll charges)??
Finaly, i'm not expert in electronics, but i would STRONGLY advise against using power line voltages and transformers (as the other user suggested ) for producing a local ring signal of 50-60Hz. A (free) call to the fax from another mobile/fixed line seems not that a big hussle to me.
Uncle M> > I use a fax machine as a printer, very neat use of a laptop's fax/
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