From: traurig@ncavax.decnet.lockheed.com
Subject: Re: PD soft. for telephone pagers
Organization: Sanders Associates
Date: Tue, 28 Jul 92 13:20:21 GMT

In article <l795clINN1jr@alshain.usc.edu> lkimes@alshain.usc.edu (Lance 'Moof'
Kimes) writes:
>
>In article <62926@cup.portal.com>, MacUserLabs@cup.portal.com (Stephan -
Somogyi) writes:
>|> lkimes@alshain.usc.edu (Lance 'Moof' Kimes) writes:
>|> 
>|> >Can the Motorola Advisor model receive straight text input from a modem &
>|> >terminal program?
>|> 
>|> No, since there is no direct connection to it. The host at the pager
company
>|> basically encodes the contents of the page into a packet and transmits it.
>|> There is never a "connection" to the pager. The pager itself is a simple RF
>|> receiver and decoder.
>|> 
>|> How do you get an alphanumeric page to your Advisor now?
>|> 
>|> __________________________________________________________________________
>|> Stephan Somogyi                don't forget to vot                 MacUser
>
>
>This is the second time you've pointed out the obvious. I do appreciate
>any help, but I(and most people) already realize that until my modem 
>sprouts an antennae, I'm calling a 'host' that retransmits data it receives.
>So I'll restate the obvious.


	In Stephan's defense, I think he answered your original question as you stated
it!  Your initial posts made it appear that you did not understand "the
obvious".


>Do all or most pagering companies use DTMF in receiving the messages 
>transmitted to the paging companies

Only on so called "digital" pagers - see below.

>(ie: same protocal used by modems)?

DTMF is not used by modems except when dialing the phone!

>Are do they expect some special, proprietary modulated frequencies that 
>represent alphabetical characters to them?

No, just a regular modem connection will do it. This only applies to
"alphanumeric" pagers - see below for more detail.

>If they do, does anyone have
>C code that will instruct Hayes modems to transmite these special tones?

Modem, Hayes or otherwise, can not transmit "special tones".  Nor do they need
to - see below.

>My present paging company doesn't have a tech dept that's accessible
>to those outside of their company, so they can't tell me either.
>But they do offer a software package that's works with DOS machines.
>They just don't know how it works.

Ah, a prepackaged front end, like on Prodigy (yuck!) or Compuserve Navigator. 
Call the software and/or paging equipment manufacturer for more info, although
you can probably reverse engineer it by monitoring the serial line with another
computer and sending a few pages.

For those that are interested:

	There are four basic types of pagers: tone alert, tone alert w/voice (or voice
pager), digital, and alphanumeric.  The labels digital and alphanumeric might
be considered arbitrary, but that is what they are called in the pager
industry.

	The tone alert pager only beeps when it is activated.  The most common form of
activation is a phone number assigned to that pager.  When you dial it, a
computer answers, knows what line it is, and transmits the proper series of
tones over a radio frequency to activate the pager (it beeps).  You don't here
anything on the phone except maybe a beep to confirm the computer has processed
your request.  You hang up.  To call one of these pagers from your computer,
simply have your modem dial the phone number and then hang up when it answers.

	The tone alert with voice is not a good choice for computer activation unless
your computer can synthesize speech over the phone line.  The method of
activation is the same as for the tone alert, however after you hear the beep
(about the same time the pager is beeping) you can speak for a certain amount
of time.  Your voice is transmitted over the radio and will be heard on the
target pager.

	The actual signals transmitted over the radio to activate the above types of
pagers can be anywhere from one to (a bunch - I forget how many) tones.  These
tones are fairly well standardized, although each manufacturer has a few
proprietary ones.  They ARE NOT DTMF tones.

	The digital pager is the most popular option these days.  These are the pagers
that display "phone numbers".  To activate these pagers you dial a phone
number, just like for the tone alert pagers.  When the computer answers, it
waits for you to dial in a number on your phone and hang up.  Then, using the
special radio tones, it transmits the appropriate activation tones over the
radio, and then transmits the number that was dialed in by the caller using a
similar set of tones.  The nice thing about these pagers is you don't have to
dial in just a phone number - any sequence of DTMF tones shorter than whatever
the allowed maximum for that pager is OK.  This way you can send messages based
on prearranged codes.  These pagers are also easily accessed by having your
computer dial the appropriate phone number, wait for an answer, and dial
another number, code, whatever.

	Finally there are the alphanumeric pagers, the ones that can display an entire
text message.  Access is usually by answering service.  To access these by
computer, you must be signed up with a system that provides computer access
(duh!).  In this case, your computer must call the paging computer, log in, and
send the appropriate commands.  The interface is usually menu driven.  The only
time your modem sends DTMF tones is when calling the paging service computer! 
After that it's just a plain old modem connection, running at whatever baud
rate/protocol the service and you support.

Scott (traurig@ncavax.decnet.lockheed.com)