Thanks for downloading the Modem Doctor. The Documentation goes into
  great detail about how the Modem Doctor works and what it can do for you.
  In summary, here are the new features added in Version 3.0S and 3.0R;

         **  Support for COM 1 through COM 4 (Shareware Version)
         **  Support for COM 1 through COM 8 using system IRQ's 3,4,5
             or 7 (Registered Version)

         **  Detection of Uart type and special diagnostics for
             8250-B, 16450/8250A, 16550 and 16550AN's

         **  Baud Rates from 300 to 38400 bps (Registered Version)
         **  Support for Courier HST/Dual Standard/V.32 Modems (Both)
         **  Auto-detection of Modems that use &T0 diagnostics (Both)
         **  Auto log-in of COMM ports 1 - 4 to DOS for use by other
             programs (Both)

         **  Manual log-in of up to 8 COMM ports for Non-Standard
             Hardware,including those with defective Uarts (on manual
             selection).  (Registered Version)

         **  On-screen Display of all 8250 /16450/ 16550 UART
             registers (Both)

         **  On-screen Display of Modem S-Registers (Both)
         **  Full Diagnostic tests of UART and RS-232 Channels
             including; (Both)
                -- ALL UART REGISTERS
                -- ALL RS-232 Handshaking Signals
                -- 8259 Interrupt Controller Mask Registers
                -- Digital Loopback UART Tests including Chips
                   with Tri-stated OUT2 signals (Registered)
                -- Analog Loopback Data Tests   (Registered)
         **  Full Diagnostic Checks of "AT" Instruction Set
             Modems; (Both)
                -- Carrier Tests on both Originate and Answer
                   Frequencies (!Improved!)
                -- Carrier Test interface for "Dumb" Modems or Data
                   Channels (!Improved!)
                -- Modem Microprocessor Command Channel Diagnostics
                -- Support for High Speed Modems
                -- Support for Modems that use the alternate &T0 self
                   test mode
                -- Escape Keys added for quick aborting of tests (Both)

         **  Interactive Mode with 4K Communications Buffer for; (Both)
                -- TTY mode Interactive Communications over serial
                   port or Modem while on-line
                -- Custom Designed Tests...Help Menu Included
                -- On-Line "Hot-key" Viewing of UART Registers

         **  Hot-Keys for selecting the Baud rate and to Force a
             Modem Microprocessor test mode.  (Both)

         **  User Selection of Modem Drivers. Like Printer Drivers,
             these software modules add more selections and more test
             capability to The Modem Doctor. (Both)

         **  New Status Bar that continuously displays the Port,
             Speed, Microprocessor Status, and Modem Driver
             selections. (Both)

         **  Command Line Mode interface for setting up a modem to an
             initialization string contained in a user created file;
             (Registered Version)
               -- A Small text file contains the port (and optional
                  address), the speed, and the string to send to the
                  modem. Any text editor can create the file at any
                  time!

  If you are a registered user you can update to the latest version very
  inexpensively. See the Order.frm or read the docs for details on how to
  update and how to register your copy of the Modem Doctor