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 Author:  George Radojevic 
 Subject:  Orphanware RS232C serial port device 
 Date:  May 15, 1988
 
 
 
 This paper will demonstrate the ability of the Orphanware RS232C 
 serial port device for the Adam computer to interface with a dumb 
 terminal while under the CP/M operating system.
 
 The RS232C device is a serial port which can be used to pass data 
 from the computer to a peripheral connected by the port.  Files 
 can be copied to a serial printer thru the port.  A modem can be 
 used with the port to allow communication thru telephone lines.  
 Finally, the port can be used to get 80 columns from your Adam.
 
 An 80 column video unit from Ophanware or Eve Electronics will 
 produce 80 columns at a price of about $225 and $325 
 respectively.  They require that you have a monochrome monitor 
 which can handle 80 column output.  The color television or color 
 monitor you use for running SMARTBASIC programs, SMARTLOGO 
 drawings, ADAMCALC spreadsheets, ADAMLINK communications, and 
 many other non CP/M type programs will not work with the 80 CVU.  
 This means you need 2 monitors, one for color and one for 80 
 columns.  There is a rumor that Commordore has come out with a 
 monitor which has both modes; color with 40 columns and 
 monochrome with 80 columns.  A report on that prospect should be 
 done some time in the near future.  The monitor costs about $200.
 
 A dumb terminal will cost at least $450 if you don't already have 
 one.  But, if you do already own one, you can use it with the 
 serial port to get the same 80 columns you would if you had the 
 80 CVU.
 
 The port costs about $75 and plugs into the expansion slot on the 
 right hand side of the computer.  The port was created by 
 Orphanware for use with a modem, but it can be used with a 
 printer and a dumb terminal.  For $75 you get a lot of 
 possibilities.
 
 The trick of using the port with a dumb terminal is modifying the 
 pin configuration on the cable connector on the serial port, 
 adjusting the port speed and terminal speed to the same settings, 
 and redirecting the console input and output from your Adam 
 keyboard and monitor to your terminal keyboard and monitor.
 
 The port connector pin configuration must be changed because it 
 was originally set up for operation with a modem, not a terminal.  
 The correct pin configuration conversion for a terminal follows:
 
      Port Connector Pin Terminal Connector Pin
      ------------------ ----------------------
              2 <-----------------> 3
              3 <-----------------> 2
              5,6,8 <-----------------> 20
              7 <-----------------> 7
             20 <-----------------> 5,6,8
 
 The speed at which the port runs is controlled by system 
 software.  This means that there aren't any switches to flip on 
 the hardware to change port speed.  ABP25.COM and IMP.COM have 
 both been used successfully to change the port speed.  It's 
 default speed is 1200bps, but it operates all the way up to 
 19200bps.  When using ABP25.COM, Serial Port #1 is the one you 
 want to change from 1200bps to whatever your terminal is set for.  
 I originally believed that Serial Port #2 was the one which 
 should be modified, but Port #1 had the only affect.  The port 
 and terminal speeds should be set prior to redirection.
 
 The console device is normally the combination of the Adam 
 keyboard for input, and a monitor or television for video output.  
 CON in the normal combination is set to CON:=CRT:
 
 Redirection is accomplished by using STAT.COM in this way: STAT 
 CON:=TTY:  The input will then come from the terminal keyboard 
 and the output will come from the terminal monitor.  All of this 
 will happen thru the RS232C serial port.  Redirection can also be 
 accomplished with ABP25.COM.
 
      In conclusion:
 
      80 column video unit $225
      Monochrome monitor 150
      RS232C serial port 75
      ----------------------------------
                total $450
 
 With the above setup you can have 80 columns under CP/M and use 
 the serial port with a modem or printer.
 
      Monochrome dumb terminal $450
      RS232C serial port 75
      ----------------------------------
                total $525
 
 With the above setup you can have 80 columns under CP/M, but 
 cannot use the serial port with a modem at the same time. The 
 advantage to having this setup is the ability to use the terminal 
 and a modem without the Adam.  And if you already have a terminal 
 you can subtract the price of one from the total.
 
 This paper was written with the use of:
 
 Apple Macintosh SE using MacTerminal in VT100 mode for the 
 terminal.  Colecovision Adam using an editor from TURBO PASCAL 
 for the editor.
 
 TURBO PASCAL has many possible screen drivers which can be 
 modified for the terminal type you have.  I used DEC Rainbow 
 terminal type when asked, because it most closely emulates a 
 VT100 terminal which the Macintosh communications program was 
 running.
 
 
odem or printer.
 
      Monochrome dumb terminal $450
      RS232C serial port 
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