Oakland CPM Archive/oakcpm.iso/cpm/turbopas/pmodem.ark/ROS.MDM

Text File | 1987-02-22 | 7.8 KB | 268 lines

{ ROSMDM.INC - Remote Operating System Modem Dependent Routines }

{ File:        ADC4.MDM----->  SMARTEAM.MDM
  Description: This driver is designed to support modems which use the 'AT'
               command set such as the Hayes Smartmodem, the Courier 2400, and
               others.  It ensures that the modem has correctly received the
               command sent from the computer by monitoring the echo from the
               modem.  This prevents potential problems from modems which
               reset or lose characters when a call and a command are received
               simultaneously.
  Date:        7/28/28
  Authors:     Jacques Durosier, Steve Fox
  Credits:     Chris Hueuser, Richard Transue, Steve Holtzclaw

  Description: Make computer independent by using calls to channel drivers
               instead of direct port accesses, comment update, and code
               cleanup.
  Date:        9/7/85
  Author:      Mick Gaitor, Steve Fox

  Description: Improve operation.
  Date:        10/26/85
  Author:      Steve Fox

  Description: Use verbal result codes instead of numeric so that modems
               which do not have a verbal/numeric switch can use closed loop
               driver.
  Date:        4/13/86
  Author:      Steve Fox

  Description: Added code to turn speaker off and comment switch settings
               for the ADC 1200 Phone Modem (10) switches.
  Date:        6/12/86
  Author       Terry Smith

  The following hardware configuration is assumed:

     DCD (pin 8)  is supported and used by the channel procedures
     DTR (pin 20) is supported and used by the channel procedures
     RI  (pin 22) is not supported

For the Courier 2400 and the Smarteam 1200, the switches should be set as
follows:

     1 = up    DTR supported, do not force to always logic true.
     2 = up    Send result codes as digits.
     3 = down  Send result codes to the host.
     4 = up    Echo characters when in command state.
     5 = down  Do not answer the telephone.
     6 = up    DCD supported, do not force to always logic true.
     7 = up    Single line RJ11 telephone connection to modem.
     8 = down  Enables modem command recognition when in command state.


    For the ADC 1200 Phone Modem:  Remember  UP = Open   Down = On

    1 = down   Enable command recognition
    2 = N/A    Activates beep (your choice)
    3 = up     Use Hayes command set
    4 = down   Do not answer calls
    5 = up     Echo commands in command mode
    6 = down   Send result codes
    7 = up     Send result codes in English
    8 = up     DTR supported
    9 = N/A    Auto redial selector
   10 = up     Respond to DCD

}

const
    { Modem command strings }
  mdCmdInit   = 'ATH0S0=0S2=3E1X1V1Q0M0'^M;
               { AT                   = get attention
                   H0                 = ensure phone hung up
                     S0=0             = disable modem auto answer function
                         S2=3         = change escape code from '+' to ETX
                             E1       = echo on
                               X1     = extended response set
                                 V1   = word response
                                   Q0 = send modem responses
               }
  mdCmdBusy   = 'ATH1'^M;
  mdCmdHangup = 'ATH'^M;
  mdCmdAns    = 'ATA'^M;

    { Modem result codes }
  mdRspOkay   = 'OK';                       { Command executed with no errors }
  mdRspCnct3  = 'CONNECT';                  { Carrier detect at 300 bps }
  mdRspRing   = 'RING';                     { Ring signal detected }
  mdRspNoCar  = 'NO CARRIER';               { Carrier lost or never heard }
  mdRspError  = 'ERROR';                    { Error in command execution }
  mdRspCnct12 = 'CONNECT 1200';             { Carrier detect at 1200 bps }
  mdRspCnct24 = 'CONNECT 2400';             { Carrier detect at 2400 bps }
  mdRspOffhk  = 'OFF HOOK';                 { Modem off hook}

type
  Str13       = string[13];

procedure mdQuiet;
{ Wait for 100 ms of silence }
  var
    i: integer;
  begin
    i := 0;
    repeat
      if ch_inprdy
        then
          begin
            i := ch_inp;
            i := 0
          end
        else
          begin
            delay(5);
            i := succ(i)
          end
    until i >= 20;
  end;

function mdReady(sec: integer): boolean;
{ Check for input from the modem }
  var
    ctr: integer;
  begin
    ctr := round(6.0 * lps);
    while (not ch_inprdy) and (sec > 0) do  { Loop until ready or timeout }
      begin
        ctr := pred(ctr);
        if ctr <= 0
          then
            begin
              sec := pred(sec);
              ctr := round(6.0 * lps)
            end
      end;
    mdReady := sec > 0
  end;

function mdReply(bt: byte; sec: integer): boolean;
{ Compare the input to what was sent out }
  begin
    if mdReady(sec)
      then mdReply := bt = ch_inp
      else mdReply := FALSE
  end;

function mdResult: Str13;
{ Get result code from modem }
  var
    ch: char;
    result: Str13;
  begin
    result := '';
    repeat
      if mdReady(5)
        then ch := chr($7F and ch_inp)      { Get input }
        else
          begin
            result := mdRspError;
            ch := LF
          end;
      if ch in [' '..'_']
        then result := result + ch;
      if length(result) > 12
        then delete(result, 1, 1)
    until ch = LF;
gotoxy (1,1);
    mdResult := result
  end;

function mdCommand(stg: StrPr; sec: integer): Str13;
{ Send a command string to the modem }
  var
    OK: boolean;
    bt: byte;
    i: integer;
  begin
    mdQuiet;
    i := 1;
    repeat
      bt := ord(stg[i]);
      i := succ(i);
      ch_out(bt);                           { Send the character }
      OK := mdReply(bt, sec)
    until (not OK) or (i > length(stg));
    if OK
      then OK := mdReply(ord(CR), sec);
    if OK
      then OK := mdReply(ord(LF), sec);
    if OK
      then mdCommand := mdResult
      else mdCommand := mdRspError
  end;

procedure mdInit;
{ Ensure the modem is hung up, initialized, and ready to wait for a ring. }
  var
    tries: integer;
  begin
    tries := 3;
    ch_init;                                { Initialize the remote channel }
    ch_on;
    ch_set(1200);                            { Set the channel speed }
    repeat
      tries := pred(tries)
    until (mdCommand(mdCmdInit, 5) = mdRspOkay) or (tries <= 0);
    mdQuiet
  end;

procedure mdBusy;
{ Take modem off hook to present a busy signal to incoming callers }
  var
    tries: integer;
  begin
    tries := 3;
    repeat
      tries := pred(tries)
    until (mdCommand(mdCmdBusy, 5) = mdRspOkay) or (tries <= 0)
  end;

procedure mdHangup;
{ Hangup modem }
  var
    i, tries: integer;
    result: Str13;
  begin
    tries := 3;
    repeat
      ch_off;
      delay(500);
      ch_on;
      if ch_carck
        then
          begin
            delay(1000);
            for i := 1 to 3 do
              ch_out(ord(ETX));
            delay(1000);
            result := mdCommand(mdCmdHangup, 5)
          end;
      tries := pred(tries)
    until not ch_carck or (tries <= 0)
  end;

function mdRing: boolean;
{ Determine if the phone is ringing }
  begin
    if ch_inprdy
      then mdRing := mdResult = mdRspRing
      else mdRing := FALSE
  end;

procedure mdAns;
{ Answer call and set system to correct baud rate }
  var
    result: Str13;
  begin
    result := mdCommand(mdCmdAns, 35);      { Let the modem answer }
    if result = mdRspCnct3
      then ch_set(300)
    else if result = mdRspCnct12
      then ch_set(1200)
(*  else if result = mdRspCnct24
      then ch_set(2400)
*)    else mdHangup;
    mdQuiet
  end;