Voiceless Pulse Dialer

[G-Man]

The pulsing contacts of ANY (pulse) dial need to be placed in SERIES of any other components (or in the case, modem) for the dial to work.

[dsk]

I guess you are close, connect the modem across the right set of dial contacts. Give it a try. Ringers across the line may slow down the data speed. Solved by hook switch, zenerdiodes, or quadrac.....
dsk

[luns]

I think that with the modem off hook, the line voltage is too low for the dialor to work.

Voltage to both IC's sits at 2.5v regardless of the modem or any other device being on or off hook. That seems low but the datasheets indicate that I'm fine so long as I don't go under 2.2v.

Is that 2.5v while standing by, or during dialing while the ON contacts are closed?

I would go back to trying to get the rotary dialing working.

How? Just a few posts above I was told that you cannot pulse dial with other devices off hook.

It was in the next paragraph.

First step is to get the actual dialing going. This is really simple to start; just put the DP (dial pulse - S3 in your anti-tinkle figure) contacts in SERIES with the Hayes modem. When the modem is off hook, the dial should be able to dial.

We'll ultimately end up with something close to your first circuit digram, but let's build up to it instead of starting with everything. Set aside the hook switch, ringer, snubber, and let's start with just the DP contacts. Connect tip (green wire) from your modem to tip of the incoming phone line, and put a DP contact on the incoming ring (red wire), and the other on ring for the modem. Now see if you can dial off when you put take the modem off hook.

[unbeldi]

I think that with the modem off hook, the line voltage is too low for the dialor to work.

Voltage to both IC's sits at 2.5v regardless of the modem or any other device being on or off hook. That seems low but the datasheets indicate that I'm fine so long as I don't go under 2.2v.

If the voltage is indeed at 2.5 V when either off– or on-hook, it must mean that it is clamped at that level intentionally to guarantee operation of the chips, which seem reasonable if carefully designed.

For normal telephone operation with a standard CB telephone circuit, 2.5 V is probably not enough, unless a local battery induction coil is used with a very low impedance in the primary winding and/or with special low-impedance transmitter.

[luns]

I would go back to trying to get the rotary dialing working.

How? Just a few posts above I was told that you cannot pulse dial with other devices off hook.

I guess I should clarify this a little. The line sees an on-hook condition only if everything on the line is on-hook. If one or more devices is off-hook, then it's considered off-hook. Pulse dialing signals with pulses of the on-hook condition. This can't happen if one device is pulsing on-hook, while somebody else is off hook.

With my suggestion of putting the DP contacts in series, the only thing that goes off hook is the modem. The dial is not considered a separate off-hook device on the line trying to dial, it's part of the wiring to the modem. When the series contacts open, as far as the CO is concerned, it looks like the modem is being pulsed on-hook - it looks to the line like it's the modem itself dialing.

[MIPS]

Th suggestion in the thread asking about the Dialor 1.2 revealed that disconnecting R6 allowed you to externally feed the adapter. Once a few other bugs were figured out the hook switch module was modified slightly and the adapter mounted on a separate board. Everything seems to work now.