diff --git a/include/tabby/link.h b/include/tabby/link.h
index 9c9aa79..046deac 100644
--- a/include/tabby/link.h
+++ b/include/tabby/link.h
@@ -1,6 +1,7 @@
 #ifndef _TABBY_LINK_H
 #define _TABBY_LINK_H
 
+#include <stdint.h>
 #include <string.h>
 #include <unistd.h>
 #include <fcntl.h>
@@ -10,15 +11,15 @@
 
 #include <tabby/clock.h>
 
-#define TABBY_LINK_BAUD B115200
+#define TABBY_LINK_BAUD B57600
 
 int tabby_link_open(const char *dev);
 
 int tabby_link_close(int fd);
 
-ssize_t tabby_link_send(int fd, char *buf, uint16_t len);
+ssize_t tabby_link_send(int fd, void *buf, uint16_t len);
 
-ssize_t tabby_link_recv(int fd, char *buf, uint16_t len);
+ssize_t tabby_link_recv(int fd, void *buf, uint16_t len);
 
 int tabby_link_set_clock_source(int fd, tabby_clock_source source);
 
diff --git a/src/link.c b/src/link.c
index cc35070..69ec0af 100644
--- a/src/link.c
+++ b/src/link.c
@@ -1,10 +1,11 @@
 #include <tabby/link.h>
+#include <tabby/command.h>
 
 int tabby_link_open(const char *dev) {
     int fd;
     struct termios attr;
 
-    if ((fd = open(device, O_RDWR | O_NOCTTY)) < 0) {
+    if ((fd = open(dev, O_RDWR | O_NOCTTY)) < 0) {
         goto error_open;
     }
 
@@ -39,9 +40,9 @@ int tabby_link_close(int fd) {
     return close(fd);
 }
 
-ssize_t tabby_link_send(int fd, char *buf, uint16_t len) {
+ssize_t tabby_link_send(int fd, void *buf, uint16_t len) {
     uint8_t header[3] = {
-        TABBY_COMMAND_SEND, len & 0xff00 >> 8, len & 0xff
+        TABBY_COMMAND_SEND, (len & 0xff00) >> 8, len & 0xff
     };
 
     if (write(fd, &header, sizeof(header)) < 0) {
@@ -54,7 +55,7 @@ error_write_header:
     return -1;
 }
 
-ssize_t tabby_link_recv(int fd, char *buf, uint16_t len) {
+ssize_t tabby_link_recv(int fd, void *buf, uint16_t len) {
     return read(fd, buf, (size_t)len);
 }