diff --git a/chrony.texi b/chrony.texi
index 3629d35..90bb260 100644
--- a/chrony.texi
+++ b/chrony.texi
@@ -2176,9 +2176,10 @@ Software that can be used as a source of timestamps includes
 @item SOCK
 Unix domain socket driver.  The parameter is a path to the socket
 which is used as the source of timestamps.  This is as a better
-alternative to SHM, it does not require polling and the offset
-resolution is not limited to microsecond.  The format for messages
-sent over the socket is declared in file @code{refclock_sock.c}.
+alternative to SHM, it does not require polling, the offset
+resolution is not limited to microsecond and it supports PPS.
+The format for messages sent over the socket is declared in file
+@code{refclock_sock.c}.
 @end table
 
 The @code{refclock} command also supports a number of subfields (which
diff --git a/refclock_sock.c b/refclock_sock.c
index c141010..91dbbc9 100644
--- a/refclock_sock.c
+++ b/refclock_sock.c
@@ -38,6 +38,7 @@
 struct sock_sample {
   struct timeval tv;
   double offset;
+  int pulse;
   int leap;
 };
 
@@ -53,7 +54,11 @@ static void read_sample(void *anything)
   if (recv(sockfd, &sample, sizeof (sample), 0) != sizeof (sample))
     return;
 
-  RCL_AddSample(instance, &sample.tv, sample.offset, sample.leap);
+  if (sample.pulse) {
+    RCL_AddPulse(instance, &sample.tv, sample.offset);
+  } else {
+    RCL_AddSample(instance, &sample.tv, sample.offset, sample.leap);
+  }
 }
 
 static int sock_initialise(RCL_Instance instance)