{NULL,                          ZSAU_UNKNOWN}
 };
 
-/*
- * Get integer from char-pointer
- */
-static int isdn_getnum(char *p)
-{
-       int v = -1;
-
-       gig_dbg(DEBUG_EVENT, "string: %s", p);
-
-       while (*p >= '0' && *p <= '9')
-               v = ((v < 0) ? 0 : (v * 10)) + (int) ((*p++) - '0');
-       if (*p)
-               v = -1; /* invalid Character */
-       return v;
-}
-
-/*
- * Get integer from char-pointer
- */
-static int isdn_gethex(char *p)
-{
-       int v = 0;
-       int c;
-
-       gig_dbg(DEBUG_EVENT, "string: %s", p);
-
-       if (!*p)
-               return -1;
-
-       do {
-               if (v > (INT_MAX - 15) / 16)
-                       return -1;
-               c = *p;
-               if (c >= '0' && c <= '9')
-                       c -= '0';
-               else if (c >= 'a' && c <= 'f')
-                       c -= 'a' - 10;
-               else if (c >= 'A' && c <= 'F')
-                       c -= 'A' - 10;
-               else
-                       return -1;
-               v = v * 16 + c;
-       } while (*++p);
-
-       return v;
-}
-
 /* retrieve CID from parsed response
  * returns 0 if no CID, -1 if invalid CID, or CID value 1..65535
  */
 static int cid_of_response(char *s)
 {
-       int cid;
+       unsigned long cid;
+       int rc;
 
        if (s[-1] != ';')
                return 0;       /* no CID separator */
-       cid = isdn_getnum(s);
-       if (cid < 0)
+       rc = strict_strtoul(s, 10, &cid);
+       if (rc)
                return 0;       /* CID not numeric */
        if (cid < 1 || cid > 65535)
                return -1;      /* CID out of range */
                case RT_ZCAU:
                        event->parameter = -1;
                        if (curarg + 1 < params) {
-                               i = isdn_gethex(argv[curarg]);
-                               j = isdn_gethex(argv[curarg + 1]);
-                               if (i >= 0 && i < 256 && j >= 0 && j < 256)
-                                       event->parameter = (unsigned) i << 8
-                                                          | j;
-                               curarg += 2;
+                               unsigned long type, value;
+
+                               i = strict_strtoul(argv[curarg++], 16, &type);
+                               j = strict_strtoul(argv[curarg++], 16, &value);
+
+                               if (i == 0 && type < 256 &&
+                                   j == 0 && value < 256)
+                                       event->parameter = (type << 8) | value;
                        } else
                                curarg = params - 1;
                        break;
                case RT_NUMBER:
+                       event->parameter = -1;
                        if (curarg < params) {
-                               event->parameter = isdn_getnum(argv[curarg]);
-                               ++curarg;
-                       } else
-                               event->parameter = -1;
+                               unsigned long res;
+                               int rc;
+
+                               rc = strict_strtoul(argv[curarg++], 10, &res);
+                               if (rc == 0)
+                                       event->parameter = res;
+                       }
                        gig_dbg(DEBUG_EVENT, "parameter==%d", event->parameter);
                        break;
                }