diff --git a/src/ca/cac.cpp b/src/ca/cac.cpp
index 1b6a8bc31..9c615fc72 100644
--- a/src/ca/cac.cpp
+++ b/src/ca/cac.cpp
@@ -94,7 +94,7 @@ cac::cac () :
         osiGetUserNameReturn gunRet;
 
         gunRet = osiGetUserName ( tmp, sizeof (tmp) );
-        if (gunRet!=osiGetUserNameSuccess) {
+        if ( gunRet != osiGetUserNameSuccess ) {
             tmp[0] = '\0';
         }
         len = strlen (tmp) + 1;
@@ -841,3 +841,12 @@ bool cac::createChannelIO (const char *pName, cacChannel &chan)
     return true;
 }
 
+void cac::lock () const
+{
+    semMutexMustTake ( this->ca_client_lock );
+}
+
+void cac::unlock () const
+{
+    semMutexGive ( this->ca_client_lock );
+}
diff --git a/src/ca/cacChannel.cpp b/src/ca/cacChannel.cpp
index 7e773f57b..0ff26047e 100644
--- a/src/ca/cacChannel.cpp
+++ b/src/ca/cacChannel.cpp
@@ -17,8 +17,6 @@
 
 #include "iocinf.h"
 
-osiMutex cacChannel::defaultMutex;
-
 cacChannel::cacChannel () : pChannelIO (0) 
 {
 }
@@ -33,10 +31,8 @@ cacChannel::~cacChannel ()
 void cacChannel::attachIO (cacChannelIO &io)
 {
     assert ( ! this->pChannelIO );
-    this->lock ();
     this->pChannelIO = &io;
     this->ioAttachNotify ();
-    this->unlock ();
 }
 
 int cacChannel::read ( unsigned type, unsigned long count, cacNotify & notify )
@@ -238,16 +234,6 @@ void cacChannel::connectTimeoutNotify ()
 {
 }
 
-void cacChannel::lock ()
-{
-    this->defaultMutex.lock();
-}
-
-void cacChannel::unlock ()
-{
-    this->defaultMutex.unlock();
-}
-
 unsigned cacChannel::readSequence () const
 {
     if ( this->pChannelIO ) {
@@ -271,3 +257,17 @@ void cacChannel::incrementOutstandingIO ()
         this->pChannelIO->incrementOutstandingIO ();
     }
 }
+
+void cacChannel::lock () const
+{
+    if ( this->pChannelIO ) {
+        this->pChannelIO->lock ();
+    }
+}
+
+void cacChannel::unlock () const
+{
+    if ( this->pChannelIO ) {
+        this->pChannelIO->unlock ();
+    }
+}
diff --git a/src/ca/cacChannelIO.cpp b/src/ca/cacChannelIO.cpp
index 86be58a24..b8eec0bda 100644
--- a/src/ca/cacChannelIO.cpp
+++ b/src/ca/cacChannelIO.cpp
@@ -20,10 +20,7 @@ cacChannelIO::cacChannelIO ( cacChannel &chanIn ) :
 
 cacChannelIO::~cacChannelIO ()
 {
-    this->chan.lock ();
-    this->chan.ioReleaseNotify ();
     this->chan.pChannelIO = 0;
-    this->chan.unlock ();
 }
 
 cacLocalChannelIO::cacLocalChannelIO ( cacChannel &chan ) :
@@ -51,6 +48,11 @@ void cacChannelIO::accessRightsNotify ( caar ar )
     this->chan.accessRightsNotify ( ar );
 }
 
+void cacChannelIO::ioReleaseNotify ()
+{
+    this->chan.ioReleaseNotify ();
+}
+
 channel_state cacChannelIO::state () const 
 {
     return cs_conn;
@@ -102,14 +104,3 @@ void cacChannelIO::incrementOutstandingIO ()
 void cacChannelIO::decrementOutstandingIO ()
 {
 }
-
-void cacChannelIO::lock (void)
-{
-    this->chan.lock ();
-}
-
-void cacChannelIO::unlock (void)
-{    
-    this->chan.unlock ();
-}
-