diff --git a/src/bridge.c b/src/bridge.c
index 6d38fe2..80496db 100644
--- a/src/bridge.c
+++ b/src/bridge.c
@@ -52,7 +52,7 @@ int parse_ip_data(modem_config *cfg, unsigned char *data, int len)
   // I'm going to cheat and assume it comes in chunks.
   int i = 0;
   int ch;
-  char text[1025];
+  unsigned char text[1025];
   int text_len = 0;
 
 
diff --git a/src/debug.h b/src/debug.h
index 05b490f..0bf8671 100644
--- a/src/debug.h
+++ b/src/debug.h
@@ -52,7 +52,7 @@ void log_set_file(FILE * a);
 void log_set_level(int a);
 int log_get_trace_flags();
 void log_set_trace_flags(int a);
-void log_trace(int type, char *line, int len);
+void log_trace(int type, unsigned char *line, int len);
 void log_start(int level);
 void log_end();
 
diff --git a/src/ip.h b/src/ip.h
index ce87559..9fd9b48 100644
--- a/src/ip.h
+++ b/src/ip.h
@@ -11,7 +11,7 @@ extern int ip_init_server_conn(char *ip_addr, int port);
 extern int ip_connect(char addy[]);
 extern int ip_accept(int sSocket);
 extern int ip_disconnect(int fd);
-extern int ip_write(int fd, char *data, int len);
-extern int ip_read(int fd, char *data, int len);
+extern int ip_write(int fd, unsigned char *data, int len);
+extern int ip_read(int fd, unsigned char *data, int len);
 
 #endif
diff --git a/src/ip232.c b/src/ip232.c
index 9fd270d..1c3e069 100644
--- a/src/ip232.c
+++ b/src/ip232.c
@@ -133,7 +133,7 @@ int ip232_get_control_lines(modem_config *cfg)
 int ip232_set_control_lines(modem_config *cfg, int state)
 {
   int dcd;
-  char cmd[2];
+  unsigned char cmd[2];
 
 
   if (cfg->dce_data.ip232_is_connected) {
@@ -148,12 +148,12 @@ int ip232_set_control_lines(modem_config *cfg, int state)
   return 0;
 }
 
-int ip232_write(modem_config *cfg, char *data, int len)
+int ip232_write(modem_config *cfg, unsigned char *data, int len)
 {
   int retval;
   int i = 0;
   int double_iac = FALSE;
-  char text[1024];
+  unsigned char text[1024];
   int text_len = 0;
 
 
@@ -187,11 +187,11 @@ int ip232_write(modem_config *cfg, char *data, int len)
   return retval;
 }
 
-int ip232_read(modem_config *cfg, char *data, int len)
+int ip232_read(modem_config *cfg, unsigned char *data, int len)
 {
   int res;
   int rc;
-  char buf[256];
+  unsigned char buf[256];
   int i = 0;
   int ch;
   int text_len = 0;
diff --git a/src/ip232.h b/src/ip232.h
index ea6ab9c..fabd30e 100644
--- a/src/ip232.h
+++ b/src/ip232.h
@@ -12,7 +12,7 @@ int ip232_init_conn(modem_config *);
 int ip232_set_flow_control(modem_config *, int status);
 int ip232_get_control_lines(modem_config *);
 int ip232_set_control_lines(modem_config *, int state);
-int ip232_write(modem_config *, char *data, int len);
-int ip232_read(modem_config *, char *data, int len);
+int ip232_write(modem_config *, unsigned char *data, int len);
+int ip232_read(modem_config *, unsigned char *data, int len);
 
 #endif /*  */
diff --git a/src/line.c b/src/line.c
index 3dd407f..c829426 100644
--- a/src/line.c
+++ b/src/line.c
@@ -20,7 +20,7 @@ int line_write(modem_config *cfg, char *data, int len)
   int retval;
   int i = 0;
   int double_iac = FALSE;
-  char text[1024];
+  unsigned char text[1024];
   int text_len = 0;
   int mask = 0x7f;
   int ch;
diff --git a/src/modem_core.h b/src/modem_core.h
index 65c88dd..8c7360a 100644
--- a/src/modem_core.h
+++ b/src/modem_core.h
@@ -154,7 +154,7 @@ int get_new_cts_state(modem_config *cfg, int up);
 int get_new_dsr_state(modem_config *cfg, int up);
 int get_new_dcd_state(modem_config *cfg, int up);
 int mdm_set_control_lines(modem_config *cfg);
-void mdm_write(modem_config *cfg, char data[], int len);
+void mdm_write(modem_config *cfg, unsigned char data[], int len);
 void mdm_send_response(int msg, modem_config *cfg);
 int mdm_off_hook(modem_config *cfg);
 int mdm_answer(modem_config *cfg);
diff --git a/src/nvt.c b/src/nvt.c
index 5902a4a..2e7bb45 100644
--- a/src/nvt.c
+++ b/src/nvt.c
@@ -19,7 +19,7 @@ void nvt_init_config(nvt_vars *vars)
 
 int get_nvt_cmd_response(int action, int type)
 {
-  char rc = 0;
+  unsigned char rc = 0;
 
 
   if (type == TRUE) {
@@ -57,8 +57,8 @@ int parse_nvt_subcommand(int fd, nvt_vars *vars, unsigned char *data, int len, i
 {
   // overflow issue, again...
   nvtOption opt = data[2];
-  char resp[100];
-  char *response = resp + 3;
+  unsigned char resp[100];
+  unsigned char *response = resp + 3;
   int resp_len = 0;
   int response_len = 0;
   char tty_type[] = "VT100";
@@ -86,14 +86,14 @@ int parse_nvt_subcommand(int fd, nvt_vars *vars, unsigned char *data, int len, i
       switch (opt) {
       case NVT_OPT_TERMINAL_TYPE:
         slen = strlen(tty_type);
-        strncpy(response + response_len, tty_type, slen);
+        strncpy((char *) response + response_len, tty_type, slen);
         response_len += slen;
         break;
 
       case NVT_OPT_TERMINAL_SPEED:
 	sprintf(buf, "%i,%i", speed, speed);
 	slen = strlen(buf);
-	strncpy(response + response_len, buf, slen);
+	strncpy((char *) response + response_len, buf, slen);
 	response_len += slen;
 	break;
 	
@@ -120,9 +120,9 @@ int parse_nvt_subcommand(int fd, nvt_vars *vars, unsigned char *data, int len, i
   return rc;
 }
 
-void send_nvt_command(int fd, nvt_vars *vars, char action, int opt)
+void send_nvt_command(int fd, nvt_vars *vars, unsigned char action, int opt)
 {
-  char cmd[3];
+  unsigned char cmd[3];
 
 
   cmd[0] = NVT_IAC;
@@ -137,7 +137,7 @@ void send_nvt_command(int fd, nvt_vars *vars, char action, int opt)
 
 void parse_nvt_command(int fd, nvt_vars *vars, nvtCommand action, nvtOption opt, int parity)
 {
-  char resp[3];
+  unsigned char resp[3];
   int accept = FALSE;
   
 
diff --git a/src/nvt.h b/src/nvt.h
index 2506a43..2686eb2 100644
--- a/src/nvt.h
+++ b/src/nvt.h
@@ -45,13 +45,13 @@ typedef enum {
 typedef struct nvt_vars {
   int binary_xmit;
   int binary_recv;
-  char term[256];
+  unsigned char term[256];
 } nvt_vars;
 
 extern void nvt_init_config(nvt_vars *vars);
 extern int get_nvt_cmd_response(int action, int type);
 extern int parse_nvt_subcommand(int fd, nvt_vars *vars, unsigned char *data, int len, int speed);
-extern void send_nvt_command(int fd, nvt_vars *vars, char action, int opt);
+extern void send_nvt_command(int fd, nvt_vars *vars, unsigned char action, int opt);
 extern void parse_nvt_command(int fd, nvt_vars *vars, nvtCommand action, nvtOption opt, int parity);
 
 #endif