diff --git a/motorApp/CommSrc/Makefile.Vx b/motorApp/CommSrc/Makefile.Vx
index 1047c060..94a252b5 100644
--- a/motorApp/CommSrc/Makefile.Vx
+++ b/motorApp/CommSrc/Makefile.Vx
@@ -4,25 +4,31 @@ include $(TOP)/config/CONFIG_APP
 #----------------------------------------
 #  ADD MACRO DEFINITIONS AFTER THIS LINE
 
+# The following are used for debugging messages.
+USR_CFLAGS += -DDEBUG
+USR_CXXFLAGS += -DDEBUG
+
 # If the EPICS GPIB Module from Benjamin Franksen is used,
 # then remove the '#' from the following and add GPIB to
 # the config/RELEASE file .  If GPIB driver support is from
-# EPICS base, then leave this line commented out.
+# Marty Kraimer's mpfSerial, then leave this line commented out.
 #USR_CFLAGS += -DGPIB
 
+ifdef MPF_GPIB
 SRCS.c += ../gpibIO.c
+endif
 
 # The following is for device drivers that need serial
-# or GPIB communication support via MPF.  Define
-# MPF_SERIAL in <ioctop>/config/RELEASE.
+# communication support via MPF.  Define MPF_SERIAL in
+# <ioctop>/config/RELEASE.
+
 ifdef MPF_SERIAL
 SRCS.cc += ../serialIOMPF.cc
-MPFLIBOBJS = $(SRCS.cc:../%.cc=%.o) $(SRCS.c:../%.c=%.o)
-motorCOM_mpf: $(MPFLIBOBJS)
-	$(LINK.c) $@ $(MPFLIBOBJS)
-INSTALLS += motorCOM_mpf
 endif
 
+LIBOBJS = $(SRCS.cc:../%.cc=%.o) $(SRCS.c:../%.c=%.o)
+LIBNAME = motorCOM_mpf
+
 #Note that the command line that builds the
 #library $(LIBNAME) may be HUGE (>3kB)
 #