DOSSEG
          .MODEL    SMALL,C

DGROUP    GROUP     _DATA,STACK

_DATA	  SEGMENT   WORD PUBLIC	'DATA'
;no data needed in main program
_DATA     ENDS

STACK	  SEGMENT   PARA STACK	'STACK'
          DB   1024 DUP(?)
STACK	  ENDS

_TEXT	  SEGMENT   WORD PUBLIC 'CODE'
	  ASSUME    CS:_TEXT,DS:DGROUP,SS:DGROUP
	  EXTERN    READ_CH:NEAR,WRITE_CH:NEAR

START:    MOV       DX,DGROUP      ;SET UP DS REGISTER
          MOV       DS,DX

; call the two procedures from the module
	  CALL	    READ_CH
	  CALL	    WRITE_CH

          MOV       AX,4C00H            ;TERMINATE PROGRAM
          INT       21H

_TEXT	  ENDS
          END       START