diff --git a/src/mod/applications/mod_expr/exprpars.c b/src/mod/applications/mod_expr/exprpars.c
index 874d464806..1b8620cf30 100644
--- a/src/mod/applications/mod_expr/exprpars.c
+++ b/src/mod/applications/mod_expr/exprpars.c
@@ -12,6 +12,7 @@
 
 #include "exprpriv.h"
 #include "exprmem.h"
+#include "switch_utils.h"
 
 /* Data structure used by parser */
 typedef struct _exprToken {
@@ -314,12 +315,12 @@ int exprStringToTokenList(exprObj * obj, char *expr, exprToken ** tokens, int *c
 			default:
 				{
 					if (!comment) {
-						if (expr[pos] == '.' || isdigit(expr[pos])) {
+						if (expr[pos] == '.' || switch_isdigit(expr[pos])) {
 							/* Value */
 							start = pos;
 
 							/* Find digits before a period */
-							while (isdigit(expr[pos]))
+							while (switch_isdigit(expr[pos]))
 								pos++;
 
 							/* Find a period */
@@ -327,7 +328,7 @@ int exprStringToTokenList(exprObj * obj, char *expr, exprToken ** tokens, int *c
 								pos++;
 
 							/* Find digits after a period */
-							while (isdigit(expr[pos]))
+							while (switch_isdigit(expr[pos]))
 								pos++;
 
 							/* pos is AFTER last item, back up */
@@ -356,12 +357,12 @@ int exprStringToTokenList(exprObj * obj, char *expr, exprToken ** tokens, int *c
 								list[tpos].data.val = (EXPRTYPE) atof(buf);
 								tpos++;
 							}
-						} else if (expr[pos] == '_' || isalpha(expr[pos])) {
+						} else if (expr[pos] == '_' || switch_isalpha(expr[pos])) {
 							/* Identifier */
 							start = pos;
 
 							/* Find rest of identifier */
-							while (expr[pos] == '_' || isalnum(expr[pos]))
+							while (expr[pos] == '_' || switch_isalnum(expr[pos]))
 								pos++;
 
 							/* pos is AFTER last item, back up */
@@ -397,7 +398,7 @@ int exprStringToTokenList(exprObj * obj, char *expr, exprToken ** tokens, int *c
 								strcpy(list[tpos].data.str, buf);
 								tpos++;
 							}
-						} else if (isspace(expr[pos])) {
+						} else if (switch_isspace(expr[pos])) {
 							/* Spaces are ignored, do nothing */
 						} else {
 							/* Unknown */
diff --git a/src/mod/applications/mod_expr/exprutil.c b/src/mod/applications/mod_expr/exprutil.c
index 435288b99d..8bcb2a8a53 100644
--- a/src/mod/applications/mod_expr/exprutil.c
+++ b/src/mod/applications/mod_expr/exprutil.c
@@ -11,6 +11,7 @@
 #include "exprincl.h"
 
 #include "exprpriv.h"
+#include "switch_utils.h"
 
 
 /* Return the version number */
@@ -27,13 +28,13 @@ int exprValidIdent(char *name)
 		return 0;
 
 	/* First must be letter or underscore */
-	if (isalpha(*name) || *name == '_')
+	if (switch_isalpha(*name) || *name == '_')
 		name++;					/* Point to next letter */
 	else
 		return 0;				/* Not letter or underscore, maybe empty */
 
 	/* others can be letter, number, or underscore */
-	while (isalnum(*name) || *name == '_')
+	while (switch_isalnum(*name) || *name == '_')
 		name++;
 
 	/* When the while breaks out, we should be at the end */