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- Springboard Modules (http://discussion.visorcentral.com/vcforum/forumdisplay.php?forumid=10)
-- Thinmodem experiment (http://discussion.visorcentral.com/vcforum/showthread.php?threadid=12589)


Posted by ThirdMan on 03-05-2001 06:44 PM:

Question

Could I get a Thinmodem owner to do an experiment for me? I am wondering if the Thinmodem will dial a number if it does not detect a dialtone.

This is what I'd like you to try:
1) Plug your visor/thinmodem into a wall jack just like you normally would.
2) Pick up a handset on the same extention that the modem is plugged into and manually dial all but the last digit of your ISP.
3) While still holding the handset, have the thinmodem dial the last digit of the phone number, and see if it connects.
4) If it does connect, hang up the handset and see if it stays connected.

I'll tell you the reason why I care about this after somebody tries it... I don't want to bias you with details of my wacky scheme.

Thanks in advance for the help!

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ThirdMan


Posted by Pathdoc on 03-06-2001 01:48 AM:

Failure

I tried your experiment. I created a "test" connection under network preferences that dialed the last number. I dialed the first six numbers and then quickly hit connect. I could hear the last number dial but then all I got was a rapid busy signal. I tried five times, just in case I was not quick enough, but was unsuccessful each time. I was then able to dial in using the "regular" connection so it was not a problem with my ISP.


Posted by ThirdMan on 03-06-2001 04:16 PM:

Angry re:failure

Rats.

My grand scheme was to see if it would be possible to construct an adapter to connect a regular modem to a cell-phone hands-free set. Basically, a modified aucoustic coupler. The problem with cell phones is that you cannot get a dialtone, so you have to use the phone to do the dialing; not the modem.

If you could have dialed with the phone, and then had the modem do the talking, you would basically have a cheesey means of mobile communications.

Yes, I have read all of the cell-phone related threads, but I am curse with a 61xx nokia which needs hardware flow control, which the handspring does not provide.

Thanks again for trying...

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ThirdMan


Posted by dreichert on 03-06-2001 06:49 PM:

I do what you suggest all the time. I use a LineStein digital/analog converter on my office telephone, then manually dial the telephone at the same time the Visor dialer is going through it's dialing sequence. It definitely works both with the Thinmodem and the SpringPort modem.

Doug


Posted by ThirdMan on 03-06-2001 07:19 PM:

quote:
Originally posted by dreichert
I do what you suggest all the time. I use a LineStein digital/analog converter on my office telephone, then manually dial the telephone at the same time the Visor dialer is going through it's dialing sequence. It definitely works both with the Thinmodem and the SpringPort modem.


Fascinating... Since that works, I will endeavor to cobble together an adapter to match the output of a hands-free on a pcs phone to a regular modem jack. If it works for my Nokia and my PC, it should work on any hands-free pcs phone and a visor... I wonder how bad the connection rate will be? Analog over PCS? I'd probably be lucky to get 4800 baud!

I wonder what the odds are that I'm gonna burn out something on my phone... it's been a long time since I took any EE classes. v=ir, right?

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ThirdMan


Posted by Card Access on 03-07-2001 07:53 PM:

Unfortunately, you may be disappointed and not get *any* v.32 or v.34 (2400-baud and up) connection with an acoustic coupler to a PCS phone. (You'll have far better luck with an analog cellphone or a dual-band PCS phone while in analog roam -- as strange as this sounds).

This is because the analog audio on a PCS phone is then run through a speech codec which is designed to compress *speech*. Then, the digital bitstream is sent eventually PCS's pool and decompressed back to audio. This compression completely kills any type of QAM (quadrature-amplitude modulation) modulation scheme or its derivatives, which is what the modem will attempt to use.

When the analog mode of these phones is used, using the 'ol analog cellphone network, the modem connection will be poor, but workable.

When you make a *digital* connection to a PCS cellphone, you essentially bypass any audio compression/decompression and simply use the cellphone's digital tranceiver to provide a data 'pipe' to the PCS's pool. At that point, your data is either routed directly onto the 'net (with quick-connect services) or drives into an analog modem which in turn calls into your ISP over land line.

-Card Access


Posted by ThirdMan on 03-08-2001 03:49 PM:

Unhappy bummer.

quote:
Originally posted by Card Access
Unfortunately, you may be disappointed and not get *any* v.32 or v.34 (2400-baud and up) connection with an acoustic coupler to a PCS phone.

...

This is because the analog audio on a PCS phone is then run through a speech codec which is designed to compress *speech*. Then, the digital bitstream is sent eventually PCS's pool and decompressed back to audio. This compression completely kills any type of QAM (quadrature-amplitude modulation) modulation scheme or its derivatives, which is what the modem will attempt to use.
-Card Access



Thanks for the info...
Bummer.
I suspected as much, but I was trying not to think about it too hard so as to keep the daydream alive.

It'll cost about $10 to build an adapter for my phone, so I might go ahead and do it anyway just to say I did it. Maybe. I still have nightmares about my old 2400 baud modem... (I suppose it was better than the 300 baud attached to my C-64.)

Considering I don't have a modem in my Visor anyway, it really isn't any great loss.

__________________
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ThirdMan


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