diff --git a/ptt_unix.c b/ptt_unix.c
new file mode 100644
index 000000000..7894d84de
--- /dev/null
+++ b/ptt_unix.c
@@ -0,0 +1,69 @@
+/*
+ * WSJT is Copyright (c) 2001-2006 by Joseph H. Taylor, Jr., K1JT, 
+ * and is licensed under the GNU General Public License (GPL).
+ */
+
+#include <unistd.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+
+#if (defined(__unix__) || defined(unix)) && !defined(USG)
+#include <sys/param.h>
+#endif
+
+/* First cut, note that this only distinguishes Linux from BSDs,
+ * it will be done better later on using configure. N.B. that OSX
+ * will come up as BSD but I think this is also the right serial port
+ * for OSX. -db
+ */
+#if defined(BSD)
+#define TTYNAME "/dev/ttyd%d"
+#else
+#include <sys/io.h>
+#define TTYNAME	"/dev/ttyS%d"
+#endif
+
+/* Not quite right for size but '%d + 1' should be plenty enough -db */
+#define TTYNAME_SIZE	sizeof(TTYNAME)+1
+
+int ptt_(int *nport, int *ntx, int *iptt)
+{
+  static int nopen=0;
+  int control = TIOCM_RTS | TIOCM_DTR;
+  int fd;
+  char s[TTYNAME_SIZE];	
+
+  if(*nport < 0) {
+    *iptt=*ntx;
+    return(0);
+  }
+
+  if(*ntx && (!nopen)) {
+    snprintf(s, TTYNAME_SIZE, TTYNAME, *nport);
+    s[TTYNAME_SIZE] = '\0';
+
+    //open the device
+    if ((fd = open(s, O_RDWR | O_NDELAY)) < 0) {
+      fprintf(stderr, "device not found");
+      return(1);
+    }
+    nopen=1;
+    return(0);
+  }
+
+  if(*ntx && nopen) {
+    //    printf("Set DTR/RTS   %d   %d\n",TIOCMBIS,control);
+    ioctl(fd, TIOCMBIS, &control);               // Set DTR and RTS
+    *iptt=1;
+  }
+
+  else {
+    //    printf("Clear DTR/RTS   %d   %d\n",TIOCMBIC,control);
+    ioctl(fd, TIOCMBIC, &control);
+    close(fd);
+    *iptt=0;
+    nopen=0;
+  }
+  return(0);
+}