diff --git a/backend/medical.c b/backend/medical.c
index 5c8046ca..589f992a 100644
--- a/backend/medical.c
+++ b/backend/medical.c
@@ -31,7 +31,9 @@
 static char *CodaTable[20] = {"11111221", "11112211", "11121121", "22111111", "11211211", "21111211",
 	"12111121", "12112111", "12211111", "21121111", "11122111", "11221111", "21112121", "21211121",
 	"21212111", "11212121", "11221211", "12121121", "11121221", "11122211"};
-	
+
+int c39(struct zint_symbol *symbol, unsigned char source[]);
+
 int pharma_one(struct zint_symbol *symbol, unsigned char source[])
 {
 	/* "Pharmacode can represent only a single integer from 3 to 131070. Unlike other
@@ -66,7 +68,7 @@ int pharma_one(struct zint_symbol *symbol, unsigned char source[])
 	}
 
 	strcpy(inter, "");
-	tester = atoi(source);
+	tester = atoi((char*)source);
 
 	if((tester < 3) || (tester > 131070)) {
 		strcpy(symbol->errtxt, "error: data out of range");
@@ -114,7 +116,7 @@ int pharma_two_calc(struct zint_symbol *symbol, unsigned char source[], char des
 	strcpy(dest, "");
 	
 	strcpy(inter, "");
-	tester = atoi(source);
+	tester = atoi((char*)source);
 
 	if((tester < 4) || (tester > 64570080))
 	{
@@ -233,7 +235,7 @@ int codabar(struct zint_symbol *symbol, unsigned char source[])
 	}
 	
 	expand(symbol, dest);
-	strcpy(symbol->text, source);
+	strcpy(symbol->text, (char*)source);
 	return error_number;
 }
 
@@ -262,7 +264,7 @@ int code32(struct zint_symbol *symbol, unsigned char source[])
 	for(i = 0; i < zeroes; i++) {
 		concat(localstr, "0");
 	}
-	concat(localstr, source);
+	concat(localstr, (char*)source);
 	
 	/* Calculate the check digit */
 	checksum = 0;
@@ -309,7 +311,7 @@ int code32(struct zint_symbol *symbol, unsigned char source[])
 	}
 	
 	/* Plot the barcode using Code 39 */
-	error_number = c39(symbol, risultante);
+	error_number = c39(symbol, (unsigned char*)risultante);
 	if(error_number != 0) { return error_number; }
 	
 	/* Override the normal text output with the Pharmacode number */
diff --git a/backend/plessey.c b/backend/plessey.c
index a352c22a..a41c22ae 100644
--- a/backend/plessey.c
+++ b/backend/plessey.c
@@ -93,7 +93,7 @@ int plessey(struct zint_symbol *symbol, unsigned char source[])
 	concat(dest, "331311313");
 	
 	expand(symbol, dest);
-	strcpy(symbol->text, source);
+	strcpy(symbol->text, (char*)source);
 	return error_number;
 }
 
@@ -129,7 +129,7 @@ int msi_plessey(struct zint_symbol *symbol, unsigned char source[])
 	concat (dest, "121");
 	
 	expand(symbol, dest);
-	strcpy(symbol->text, source);
+	strcpy(symbol->text, (char*)source);
 	return error_number;
 }
 
@@ -227,7 +227,7 @@ int msi_plessey_mod10(struct zint_symbol *symbol, unsigned char source[])
 	source[h] = itoc(pump);
 	source[h + 1] = '\0';
 	expand(symbol, dest);
-	strcpy(symbol->text, source);
+	strcpy(symbol->text, (char*)source);
 	return error_number;
 }
 
@@ -382,7 +382,7 @@ int msi_plessey_mod1010(struct zint_symbol *symbol, unsigned char source[])
 	source[h + 1] = itoc(chwech);
 	source[h + 2] = '\0';
 	expand(symbol, dest);
-	strcpy(symbol->text, source);
+	strcpy(symbol->text, (char*)source);
 	return error_number;
 }
 
@@ -452,7 +452,7 @@ int msi_plessey_mod11(struct zint_symbol *symbol, unsigned char source[])
 	concat (dest, "121");
 	
 	expand(symbol, dest);
-	strcpy(symbol->text, source);
+	strcpy(symbol->text, (char*)source);
 	return error_number;
 }
 
@@ -578,13 +578,15 @@ int msi_plessey_mod1110(struct zint_symbol *symbol, unsigned char source[])
 	source[h + 1] = '\0';
 
 	expand(symbol, dest);
-	strcpy(symbol->text, source);
+	strcpy(symbol->text, (char*)source);
 	return error_number;
 }
 
 int msi_handle(struct zint_symbol *symbol, unsigned char source[]) {
 	int error_number;
-	
+
+	error_number=0;
+
 	if((symbol->option_2 < 0) || (symbol->option_2 > 4)) {
 		symbol->option_2 = 0;
 	}
diff --git a/backend/telepen.c b/backend/telepen.c
index 0383520d..dc1f36b2 100644
--- a/backend/telepen.c
+++ b/backend/telepen.c
@@ -91,7 +91,7 @@ int telepen(struct zint_symbol *symbol, unsigned char source[])
 	concat(dest, TeleTable['z']);
 	
 	expand(symbol, dest);
-	strcpy(symbol->text, source);
+	strcpy(symbol->text, (char*)source);
 	return error_number;
 }
 
@@ -99,12 +99,13 @@ int telepen_num(struct zint_symbol *symbol, unsigned char source[])
 {
 	unsigned int i, count, check_digit, glyph;
 	int error_number, input_length;
-	char dest[1000];
-	char local_source[100];
+	unsigned char dest[1000];
+	unsigned char local_source[100];
 	
 	error_number = 0;
-	strcpy(dest, "");
-	strcpy(local_source, source);
+	memset(dest, 0, 1000);
+	memset(local_source, 0, 100);
+	strcpy((char*)local_source, (char*)source);
 	input_length = ustrlen(source);
 
 	count = 0;
@@ -125,7 +126,7 @@ int telepen_num(struct zint_symbol *symbol, unsigned char source[])
 	{
 		char temp[200];
 
-		strcpy(temp, local_source);
+		strcpy(temp, (char*)local_source);
 		local_source[0] = '0';
 
 		for(i = 0; i <= input_length; i++)
@@ -136,7 +137,7 @@ int telepen_num(struct zint_symbol *symbol, unsigned char source[])
 	}
 
 	/* Start character */
-	concat(dest, TeleTable['_']);
+	concat((char*)dest, TeleTable['_']);
 
 	for (i=0; i < input_length; i+=2)
 	{
@@ -153,17 +154,17 @@ int telepen_num(struct zint_symbol *symbol, unsigned char source[])
 			glyph += 27;
 			count += glyph;
 		}
-		concat(dest, TeleTable[glyph]);
+		concat((char*)dest, TeleTable[glyph]);
 	}
 
 	check_digit = 127 - (count % 127);
-	concat(dest, TeleTable[check_digit]);
+	concat((char*)dest, TeleTable[check_digit]);
 
 	/* Stop character */
-	concat(dest, TeleTable['z']);
+	concat((char*)dest, TeleTable['z']);
 	
-	expand(symbol, dest);
-	strcpy(symbol->text, local_source);
+	expand(symbol, (char*)dest);
+	strcpy(symbol->text, (char*)local_source);
 	return error_number;
 }