FORTRAN has no hex support, this little program shows how to convert a 16 bit word (integer) to a hex as 4A1 (like CALL PDUMP output) and convert an 4A1 hex input to an integer. Note: hex just interprets exact as is bits, so has no sign value 
// JOB T
// FOR
*LIST ALL
*IOCS(CARD,TYPEWRITER,KEYBOARD,1132 PRINTER)
*ONE WORD INTEGERS
      INTEGER HEXC(16),HEXD(16),H(4),ADD
      DATA HEXC/'0','1','2','3','4','5','6','7','8','9',
     +'A','B','C','D','E','F'/
      DATA HEXD/0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15/
CONVERT DECIMAL TO HEX
      WRITE(1,1)
1     FORMAT('ENTER A 6 DIGIT INTEGER, MUST USE LEADING ZEROS')
      READ(6, 10)I
10    FORMAT(I6)
      ADD=0
      IF(I)11,14,14
11    I=I+32767+1
      ADD=8
14    J=4
15    IF(J)30,30,20
20    K=I-I/16*16+1
      IF(J-1)22,21,22
21    K=K+ADD
22    H(J)=HEXC(K)
      I=I/16
      J=J-1
      GO TO 15
30    CONTINUE
      WRITE(1, 50)H
50    FORMAT(4A1)
CONVERT BACK FROM HEX TO DECIMAL
COULD ALSO DO A READ OF H AS A 4A1
      I=0
      J=4
      DO 140 N=1,4
100   IF(J)140,140,110
110   DO 120 K=1,16
      IF(H(J)-HEXC(K))120,130,120
120   CONTINUE
C NON HEX CHAR IS AN ERROR
      I=0
      GO TO 150
130   I=I+HEXD(K)*16**(N-1)
      J=J-1
140   CONTINUE
150   WRITE(1, 10)I
      CALL EXIT
      END
// XEQ