
               Modems and Connecting to Channel 1
                               or
              "You keep hanging up on me, what gives?"


      Very few communications problems reported to us have
      anything to do with Channel 1.  We will outline common
      problems and their solutions in this bulletin, but first
      a little general orientation.

                          STATIC HAPPENS
                          --------------

      A common mis-perception among new (and not-so-new) computer
      users is to imagine that the telephone company and long-
      distance switching network is a "transparent cloud."  High-
      speed modems, which mask line-noise and push communications
      tolerances to their limit, enhance this illusion.

      "I was 300K into my transfer and you dropped carrier on me."
      "I'm only getting xxx cps, what's the problem?
      "I can't believe how slow the system is tonight."
      "My typing isn't showing up on the screen until two words later."

      Generally, all these problems can be attributed to local
      or long-distance communications network issues, better known as

                            LINE NOISE

      Problems in signal transmission and recognition can take many
      forms, and arise at many points in the PATH of a signal.
      Here's a typical analysis of a problem call:

-----------------------------------------------------------------------
Chars sent                11813      Chars Received              147
Chars lost                    0
Octets sent                7946      Octets Received             146
Blocks sent                 269      Blocks Received              53
Blocks resent           --> 275 (errors corrected)

Retrains Requested            0      Retrains Granted              0
Line Reversals                0      Blers     (line burst)  --> 173
Link Timeouts            --> 35      Link Naks               -->   1

Data Compression       V42BIS 2048/32
Equalization           Long
Fallback               Enabled
Protocol               LAPM
Speed                  14400/7200  (V.32bis speed downshift)

Disconnect Reason is DTR dropped
-----------------------------------------------------------------------

      The caller complained of buffered typing, slow system response,
      and slow transfers, and was sure it was Channel 1's problem.
      The reason?  What's known in the business as "a really crappy
      connection."

      Although V.32bis modems have become commodity items, they
      aren't equally good at dealing with line problems. Read
      PC-Magazine for details.

      "I can call MEGAZONE just fine but your modems stink."

      The above example was a long-distance connection.  Local
      callers may have identical problems that depend on the
      particular exchanges through which their calls are routed.
      If you call from download Boston, complain to NET about
      the Harrison Avenue Switching Station.

                         HELPFUL HINTS:

      1. Minimize other connections to your phone line (answering
         machine, fax, extension phones).
      2. Use a short (six feet or less) serial cable.
      3. If calling long distance, use an alternative long-distance
         connection (Bulletin 32) to diagnose problems.
      4. Have your line checked by the phone company.
      5. Don't confuse your terminal with reality.


                     THE HARDWARE -- MODEMS
                     ----------------------

      A MODEM is a MOdulator-DEModlator device.  It changes
      the digital signals (bits) sent by your computers serial
      interface to analogue signals that can be transmitted over
      telephone networks.

      Most communications programs will let you talk to the modem
      directly (though some make it difficult by presenting a menu-
      interface).  The magic command for speaking to modems is to type
      AT from the terminal screen.  AT  tells the modem to treat
      every that follows as command (see below).

      If the computer is communicating to the modem, and the modem
      is at least basically set up, it should answer back  OK .

      If it doesn't, see below, MODEM CABLES, and SOFTWARE.

      At this point, it is highly recommended that a new modem user
      spend a few minutes with the manufacturer's instruction manual,
      to locate the "commands summary and explanation" pages.

      The second command everyone should know is  AT&V .  This will
      tell -most- modems to display their configuration settings.
      See your manual if you have an unusual modem.  Most modems
      will display an "Active Profile" and one or two "Stored
      Profiles."

      Most modems come with "default" settings, which often
      need to be modified to function with bulletin board
      systems and high-speed communications.  Compare your
      modems settings with these:

      ACTIVE PROFILE:
      B1 E1 L2 M1 Q0 V1 X4 &C1 &D2 &K3 &Q0 (or &Q5)
      &R0 &S0 &X0 &Y0

      The &K and &Q settings may not be available on non-
      error-correction modems.  This (abbreviated) report says:

      Basic set
      ---------

      B1 (Bell-compatible)
      E1 (echo my typing)
      L2 (set speaker volume)
      M1 (turn on speaker so you can hear if it's dialing)
      Q0 (return result codes so your comm program can understandit)
      V1 (do it in English)
      X4 (report call progress) (may be X5,X6,X7)

      Needed for calling BBS's
      ------------------------

    * &C1 (Data Carrier Detect on)
    * &D2 (switch to command state when DTR dropped)

      Necessary for error-correcting/high speed modems
      ------------------------------------------------

    * &K3 (enable bi-directional hardware (CTS/RTS) flow-control)
      &Q0 or &Q5 (asynchonous reliable mode)

      Basic command string to set up modem for BBS operation:

      AT&E1&Q0&V1&M1&C1&D2 (add &K3Q5 for fast modems)

      Modem command set vary from manufacturer to manufacturer.
      Read your manual. Read your manual.  Read your manual.

         MODEM CABLES AND THE WHOLE UART STORY CONDENSED

      High-speed modems require serial cables which
      support hardware (CTS/RTS) flow-control.  Old
      printer cables won't necessarily work.

      If your modem is internal, you don't have to worry
      about why motherboard and serial card manufacturers
      are still designing equipment that won't support
      high-speed modems.

      If you've recently purchased a fast (V.32/V.32bis/HST)
      modem, and you are experiencing dropped characters, CRC
      errors and aborted downloads, you may need to upgrade
      your serial port to a buffered UART (16550).  Look for
      82x50B, 16x450 part numbers on the large 40-pin chips on
      the serial card to find out if your UART is brain-dead.
      Or download a buffered-UART-detector like IS16550.ZIP
      or PF271.ZIP and test your equipment.

           THE SOFTWARE -- YOUR COMMUNICATIONS PROGRAM
           -------------------------------------------

      It's a fact of of life of a sysop's life that programs designed
      to shield beginners from their modems make diagnostics more
      difficult.

      Tech Support: "Type AT and tell me what happens."
      Caller:       "There's no place to type."

      If you are using a program that came with your modem,
      like MTEZ or QLII or an old version of Crosstalk or
      Windows Terminal, go immediately to the FREE conference
      and download one the the communications programs available
      there.  Can't download?  Read on.

      Your communications program communicates with your
      modem and handles many tasks.  It must be configured
      appropriately for your particular modem, computing
      environment and the system you are calling.

      You may need to select:

      comm port  
      IRQ if you have alot of stuff in your computer
      Terminal Emulation  (ANSI-BBS or VT100/102 or RIP)
      Dialing parameters (8 DataBits N no Parity 1 stopbit)
      Dialout Speed (set for highest recommended by manufacturer)

      IF YOU HAVE A HIGH SPEED MODEM
      ----------------------------------------------------------
    * Flow Control (CTS/RTS Hardware flow control ON)
                   (counterpart to modem's &K3)

    * Baud-Rate-Detect/Adjust  OFF
                   (counterpart to modem's port-locking command)
      -----------------------------------------------------------

    * Modem initialization string  ATH0 .  Edit out long
      setup strings and especially ATZ commands.  General
      philosophy -- setup your modem with the appropriate
      settings and write them to the modem's memory (most
      have them, these days).  Keep comm program setups/changes
      as short as possible and don't let them reset your modem.

      Finally, you may need to tell your comm program about
      your hard disk:

         THE "FEATURE" THAT TRIGGERED 100,000 SUPPORT CALLS!

      Procomm, in its seminal, classic 2.4.x version that everybody
      passed all over the universe, requires a Default Download
      Directory to be specified in ALT-S setup, Files and Paths.
      If the new user doesn't type one in, the lack of an error
      message doesn't impede their call to tech support.


      APPENDIX I
      ==========

                            WEATHER
                            -------

      Believe it or not, days of rain or winter storms coating
      everything with 2 feet of ice can affect telecommunications.
      Little known fact.



                       PC-Pursuit Problems
                       -------------------

      Apparently influenced by celestial patterns or ether-sprites,
      the MABOS outdials can be flakey.  See the PC-Pursuit bulletins
      for tips on MNP enablement.  Complaints to Sprint are sometimes
      effective.

