
                      The Racal-Vadic Primer v1.0

         -----------------------------------------------------



 DISCLAIMER
------------
   Please be aware that since this mode is unsupported, there is the
possibility that SprintNet could start using a different brand of modem
which would render this feature invalid. You are strictly on your own and
therefore can not hold SprintNet responsible for not making this mode
available.

   Furthermore, this text was prepared ad hoc and is in no way a definitive
guide to the operation and/or use of either PC Pursuit or the Racal-Vadic
mode described herein. Any errors or ommisions are my own and I am sorry for
any inconvience this may cause you. Please understand that by using this
method of dialing you are totaly responsible for your actions and any
consequences as a result of said use.


 OVERVIEW
----------
   The Racal-Vadic mode is an unsupported and to date, poorly documented
feature of the outdial modems that are currently in use with PC Pursuit.
It enables you to better understand what is happening at the other end of
your connection by telling you what is happening. This type of operation is
known as "call progression" because it gives you a response as the modem
progresses through the phone call.


 ACITVATING AND DEACTIVATING THE MODE
--------------------------------------
   The first thing we will cover is how to activate and de-activate the
Racal-Vadic mode. Some of you may have already experienced the rather
unexpected "MANUAL ANSWER" response after entering the Hayes command
"ATZ". What has happened is that you have connected with a modem that
is already in the Racal-Vadic mode of operation. When you entered "ATZ",
the 'A' was sensed by the modem as the command to manualy answer the
phone line. If this happens, just press your return key. This will make
the modem return to command mode signified by the '*' prompt. While at
this prompt you could enter an 'I' and then press return. This will make
the modem <I>dle the Racal-Vadic mode and return you to the Hayes mode
of operation.

   If, on the other hand, you were to receive the normal "OK" response
from the modem after entering the "ATZ" command. You can activate the
Racal-Vadic mode by entering <CTRL>-E and pressing the return key. The
modem will now respond with "HELLO, I'M READY" and the '*' prompt.

   To summarize activation and de-activation:

      From the Hayes mode - <CTRL>-E and <RETURN> - to activate.

      From the '*' prompt - <I> and <RETURN> - to de-activate.

   I suggest getting into the habit of sending the de-activation sequence
when you first connect to a city node so that you know exactly what mode
the modem is in. You should also send an "ATZ" to make sure that the modem
is operational by seeing if the modem sends you back an "OK" response.
You can then send the activation command to enter Racal-Vadic mode.

   There are two cases where the modem will return by itself to the Hayes
mode. The first is after you connect to a BBS. The other is while you're
at the command prompt and haven't entered anything for a short period of
time. 


 DIALING
---------
   Now your ready to dial a phone number using the Racal-Vadic mode.
To do this, just enter a 'D' followed by the number you wish to dial.
For example, "D1234567", (pressing return of course!) will dial 123-4567.

   Well, we've dialed a phone number, what now? After all, any modem can
dial a number, right? But not every modem can tell you what follows...


 RESPONSE MESSAGES
-------------------
   The following is a short description of each response the Racal-Vadic
mode can give you while dialing. They are, for the most part, self-
explanatory. But there are a few things you should consider with some of
them and I'll point those out just in case.

   DIALING...   -  The modem has detected a dial tone and is now dialing
                  the phone number.

   NO DIAL TONE -  Just what it means, no dial tone was detected. Try again,
                  if you keep getting this then there is something wrong with
                  either the modem or the telephone line on that end. Contact
                  Customer Support and tell them you experienced this, tell 
                  them the city node you were connected to also.

   BUSY!        -  A busy signal has been detected. This is not the same
                  kind of BUSY as you'd get in the Hayes mode. There is
                  circuitry in the modem that can sense a busy signal, so
                  it will return to the command mode quicker to allow you
                  to decide what to do next. (Please see my note about the
                  BUSY response below also)

   RINGING...   -  Self-explanatory.

   ANSWER TONE  -  Self-explanatory.
 
   ON LINE      -  Self-explanatory.

   FAILED CALL  -  The phone rang for ten times with no answer. Either the
                  the BBS you called is down or no longer in existence, or
                  you reached someone's home and they weren't there.


 REDIALING A NUMBER
--------------------
   After you have received a BUSY! response you can re-dial the same 
phone number up to 9 times with the 'R' command. To use this command,
enter an "R" and press the return key.


 DISCONNECTING WHILE ONLINE
----------------------------
   In a manner similar to the "+++" "ATH" Hayes command sequence, there
is a two control code sequence that will dis-connect you from the BBS
you are connected to. To activate it press <CTRL>-C then <CTRL>-D.

   Prior to disconnecting from the city node, make sure the modem is not
in Racal-Vadic mode by issuing the <I>dle command. Be nice to others that
may not be aware of this mode of operation yet!


 OTHER COMMANDS
----------------
   The command 'P' or '?' will print the following list of commands that
the modem is designed to use. Since these are not needed in order to use
the Racal-Vadic mode effectively they will not be discusssed. This list
is here purely for your information.


                     A            MANUAL ANSWER
                     D            DIAL NUMBER
                     G            MANUAL ORGINATE
                     I            IDLE
                     K            PAUSE
                     O            OPTIONS
                     P,?          PRINT MENU
                     R            REDIAL
                     T            TABLE OF OPTIONS
                     CONTROL  A   ALB TEST
                     CONTROL (CD) DISCONNECT
                     CONTROL  D   REQUEST DLB TEST
                     CONTROL  H   BACKSPACE


 BEWARE THE BUSY
-----------------
   The BUSY! response primarily indicates that the phone number you dialed
was busy, common sense tell you that. What I want to point out to you in
this section is that there are other possibilities that could mean that
something else is actually occuring.


 a. CONTINUOUS BUSIES
----------------------
      The first thing to be aware of is SprintNet's exchange lock-out feature.
   This prevents you from making a long-distance call or any local calls
   to exchanges that SprintNet would be charged more than is profitable. All
   you will know is that you constantly get BUSY! responses when you dial a
   certain phone number. The response tends to be returned from the modem
   much quicker then a legitimate BUSY! for a valid phone number. This is
   not a hard and fast rule though. Two methods that are available to you
   for determining if this is the cause of the continuous busies are:

      1. -  Check the exchange lists provided by SprintNet, if the exchange is
            not listed for the number your calling, you may as well stop
            wasting anymore time calling that number. It is a victim of the
            exchange lock-out.

      2. -  If the exchange is listed but you've always received a BUSY!
            response, try this. Hang-up from SprintNet and dial the number
            direct. If you hear a busy signal you can continue trying some
            more, you may have latched onto a very, very busy system. But
            if the phone rings, hang-up immediately. This way you won't be
            charged for the call. You should then leave word with Customer
            Support or on the Net-Exchange that this happened. SprintNet may
            have a typo concerning that exchange.


 b. RINGING... BUSY!
---------------------
      There are a few things that can cause this. Although I'm not talking
   about the RING BUSY RING BUSY... loop that can occure when you first
   connect to a city node. You can get out of that by rapidly and repeatedly
   sending an "ATZ" to the modem in an effort to break out of the loop. There
   is a narrow window where this will succeed, but it can be done.

      The main cause of this is by dialing a person's phone instead of a BBS.
   This will usually be followed by a variable number of rings prior to
   getting the BUSY!. Make certain that the phone number you have is really
   a BBS. If you've never called that BBS before, you may have a case where
   the BBS folded and someone else received the phone number after the sysop
   canceled that phone line. A BBS less than 6 months old or with less than
   24 hour access can be highly suspect. New and odd-hour BBS's tend to come
   and go rather often.

      If you want to continue to dial this number, first call direct to make
   sure that it isn't a person's phone. Constantly getting a carrier signal
   in your ear is not a pleasurable experience. You would also be doing them
   a favor by letting them know that their new phone number used to be a
   BBS. If that's the case they've probably been getting a ton of bizzare
   calls, especially late at night, and could benefit from your call so that
   they can get their number changed.

      If, on the other hand, you receive a carrier signal, try the other
   Baud rate. if that doesn't work you could have reached a private system
   that is looking for a logon sequence immediately or will dis-connect you.

      Another possibility is that the BBS you've called has bombed and the
   modem is dutifully answering calls but there is no computer program 
   operating to give you feed-back.


 CAVEAT
--------
   What I've tried to cover here are the most common things that you may
run into. But, by no means have I covered every base. There are points
that I may have passed over completely because they have become second
nature to me. Others may have not been explained to your satisfaction for
the very same reason. And still other aspects may have been ignored because
I'm simply not aware of them. In each and every case I ask you to leave
word on the Net-Exchange as to what subjects are deficient or missing. That
way I can expand this text to include your suggestions for the benefit of
others.

                                    Thank you and good luck!

                                          Jack Radigan
