diff --git a/src/dev/softDev/devMbbiDirectSoftRaw.c b/src/dev/softDev/devMbbiDirectSoftRaw.c
index 72b787f77..f9cd1cd48 100644
--- a/src/dev/softDev/devMbbiDirectSoftRaw.c
+++ b/src/dev/softDev/devMbbiDirectSoftRaw.c
@@ -80,6 +80,9 @@ static long init_record(pmbbi)
 		"devMbbiDirectSoftRaw (init_record) Illegal INP field");
 	return(S_db_badField);
     }
+    /*to preserve old functionality*/
+    if(pmbbi->nobt == 0) pmbbi->mask = 0xffffffff;
+    pmbbi->mask <<= pmbbi->shft;
     return(0);
 }
 
@@ -89,5 +92,6 @@ static long read_mbbi(pmbbi)
     long status;
 
     status = dbGetLink(&pmbbi->inp,DBR_LONG,&pmbbi->rval,0,0);
+    if(status==0) pmbbi->rval &= pmbbi->mask;
     return(0);
 }
diff --git a/src/dev/softDev/devMbbiSoftRaw.c b/src/dev/softDev/devMbbiSoftRaw.c
index 6fbea2ec6..28ba4fa3b 100644
--- a/src/dev/softDev/devMbbiSoftRaw.c
+++ b/src/dev/softDev/devMbbiSoftRaw.c
@@ -72,6 +72,9 @@ static long init_record(pmbbi)
     if (pmbbi->inp.type == CONSTANT) {
 	recGblInitConstantLink(&pmbbi->inp,DBF_ULONG,&pmbbi->rval);
     }
+    /*to preserve old functionality*/
+    if(pmbbi->nobt == 0) pmbbi->mask = 0xffffffff;
+    pmbbi->mask <<= pmbbi->shft;
     return(0);
 }
 
@@ -81,5 +84,6 @@ static long read_mbbi(pmbbi)
     long status;
 
     status = dbGetLink(&pmbbi->inp,DBR_LONG,&pmbbi->rval,0,0);
+    if(status==0) pmbbi->rval &= pmbbi->mask;
     return(0);
 }
diff --git a/src/dev/softDev/devMbboDirectSoftRaw.c b/src/dev/softDev/devMbboDirectSoftRaw.c
index 61d8d0253..b06e4643c 100644
--- a/src/dev/softDev/devMbboDirectSoftRaw.c
+++ b/src/dev/softDev/devMbboDirectSoftRaw.c
@@ -70,6 +70,9 @@ struct mbboDirectRecord *pmbbo;
  
     if (pmbbo->out.type != PV_LINK)
        status = 2;
+    /*to preserve old functionality*/
+    if(pmbbo->nobt == 0) pmbbo->mask = 0xffffffff;
+    pmbbo->mask <<= pmbbo->shft;
     return status;
 } /* end init_record() */
 
@@ -77,7 +80,9 @@ static long write_mbbo(pmbbo)
     struct mbboDirectRecord	*pmbbo;
 {
     long status;
+    unsigned long data;
 
-    status = dbPutLink(&pmbbo->out,DBR_LONG, &pmbbo->rval,1);
+    data = pmbbo->rval & pmbbo->mask;
+    status = dbPutLink(&pmbbo->out,DBR_LONG, &data,1);
     return(0);
 }
diff --git a/src/dev/softDev/devMbboSoftRaw.c b/src/dev/softDev/devMbboSoftRaw.c
index 258a3bf89..d4786aad4 100644
--- a/src/dev/softDev/devMbboSoftRaw.c
+++ b/src/dev/softDev/devMbboSoftRaw.c
@@ -68,6 +68,9 @@ struct mbboRecord *pmbbo;
  
     long status;
  
+    /*to preserve old functionality*/
+    if(pmbbo->nobt == 0) pmbbo->mask = 0xffffffff;
+    pmbbo->mask <<= pmbbo->shft;
     /*dont convert*/
     status = 2;
     return status;
@@ -78,7 +81,9 @@ static long write_mbbo(pmbbo)
     struct mbboRecord	*pmbbo;
 {
     long status;
+    unsigned long data;
 
-    status = dbPutLink(&pmbbo->out,DBR_LONG, &pmbbo->rval,1);
+    data = pmbbo->rval & pmbbo->mask;
+    status = dbPutLink(&pmbbo->out,DBR_LONG, &data,1);
     return(0);
 }