diff --git a/PDP11/pdp11_defs.h b/PDP11/pdp11_defs.h
index 8f2d07ab..bf79a4f7 100644
--- a/PDP11/pdp11_defs.h
+++ b/PDP11/pdp11_defs.h
@@ -662,6 +662,8 @@ typedef struct pdp_dib DIB;
 #define INT_V_TU        15
 #define INT_V_RF        16
 #define INT_V_RC        17
+#define INT_V_DMCRX     18
+#define INT_V_DMCTX     19
 
 #define INT_V_PIR4      0                               /* BR4 */
 #define INT_V_TTI       1
@@ -705,6 +707,8 @@ typedef struct pdp_dib DIB;
 #define INT_TU          (1u << INT_V_TU)
 #define INT_RF          (1u << INT_V_RF)
 #define INT_RC          (1u << INT_V_RC)
+#define INT_DMCRX       (1u << INT_V_DMCRX)
+#define INT_DMCTX       (1u << INT_V_DMCTX)
 #define INT_PIR4        (1u << INT_V_PIR4)
 #define INT_TTI         (1u << INT_V_TTI)
 #define INT_TTO         (1u << INT_V_TTO)
@@ -751,6 +755,8 @@ typedef struct pdp_dib DIB;
 #define IPL_TU          5
 #define IPL_RF          5
 #define IPL_RC          5
+#define IPL_DMCRX       5
+#define IPL_DMCTX       5
 #define IPL_PTR         4
 #define IPL_PTP         4
 #define IPL_TTI         4
diff --git a/PDP11/pdp11_sys.c b/PDP11/pdp11_sys.c
index b0b358cf..265b011c 100644
--- a/PDP11/pdp11_sys.c
+++ b/PDP11/pdp11_sys.c
@@ -102,6 +102,7 @@ extern DEVICE xq_dev, xqb_dev;
 extern DEVICE xu_dev, xub_dev;
 extern DEVICE ke_dev;
 extern DEVICE kg_dev;
+extern DEVICE dmc_dev[];
 extern UNIT cpu_unit;
 extern REG cpu_reg[];
 extern uint16 *M;
@@ -166,6 +167,10 @@ DEVICE *sim_devices[] = {
     &xub_dev,
     &ke_dev,
     &kg_dev,
+	&dmc_dev[0],
+	&dmc_dev[1],
+	&dmc_dev[2],
+	&dmc_dev[3],
     NULL
     };
 
diff --git a/Visual Studio Projects/PDP11.vcproj b/Visual Studio Projects/PDP11.vcproj
index 811accda..030a8c27 100644
--- a/Visual Studio Projects/PDP11.vcproj	
+++ b/Visual Studio Projects/PDP11.vcproj	
@@ -215,6 +215,10 @@
 				RelativePath="..\PDP11\pdp11_dl.c"
 				>
 			</File>
+			<File
+				RelativePath="..\PDP11\pdp11_dmc.c"
+				>
+			</File>
 			<File
 				RelativePath="..\PDP11\pdp11_dz.c"
 				>
@@ -412,6 +416,10 @@
 				RelativePath="..\PDP11\pdp11_defs.h"
 				>
 			</File>
+			<File
+				RelativePath="..\PDP11\pdp11_dmc.h"
+				>
+			</File>
 			<File
 				RelativePath="..\PDP11\pdp11_io_lib.h"
 				>
diff --git a/descrip.mms b/descrip.mms
index ca932e0b..e38a742a 100644
--- a/descrip.mms
+++ b/descrip.mms
@@ -523,7 +523,8 @@ PDP11_SOURCE1 = $(PDP11_DIR)PDP11_FP.C,$(PDP11_DIR)PDP11_CPU.C,\
                $(PDP11_DIR)PDP11_RX.C,$(PDP11_DIR)PDP11_STDDEV.C,\
                $(PDP11_DIR)PDP11_SYS.C,$(PDP11_DIR)PDP11_TC.C, \
                $(PDP11_DIR)PDP11_CPUMOD.C,$(PDP11_DIR)PDP11_CR.C,\
-               $(PDP11_DIR)PDP11_TA.C,$(PDP11_DIR)PDP11_IO_LIB.C
+               $(PDP11_DIR)PDP11_TA.C,$(PDP11_DIR)PDP11_DMC.C
+               $(PDP11_DIR)PDP11_IO_LIB.C
 PDP11_LIB2 = $(LIB_DIR)PDP11L2-$(ARCH).OLB
 PDP11_SOURCE2 = $(PDP11_DIR)PDP11_TM.C,$(PDP11_DIR)PDP11_TS.C,\
                $(PDP11_DIR)PDP11_IO.C,$(PDP11_DIR)PDP11_RQ.C,\