diff --git a/src/dev/devEventTestIoEvent.c b/src/dev/devEventTestIoEvent.c
new file mode 100644
index 000000000..aad8e3c13
--- /dev/null
+++ b/src/dev/devEventTestIoEvent.c
@@ -0,0 +1,152 @@
+/* devAiTestAsyn.c */
+/* share/src/dev $Id$ */
+
+/* devAiTestAsyn.c - Device Support Routines for testing asynchronous processing*/
+/*
+ *      Original Author: Bob Dalesio
+ *      Current Author:  Marty Kraimer
+ *      Date:            6-1-90
+ *
+ *      Experimental Physics and Industrial Control System (EPICS)
+ *
+ *      Copyright 1991, the Regents of the University of California,
+ *      and the University of Chicago Board of Governors.
+ *
+ *      This software was produced under  U.S. Government contracts:
+ *      (W-7405-ENG-36) at the Los Alamos National Laboratory,
+ *      and (W-31-109-ENG-38) at Argonne National Laboratory.
+ *
+ *      Initial development by:
+ *              The Controls and Automation Group (AT-8)
+ *              Ground Test Accelerator
+ *              Accelerator Technology Division
+ *              Los Alamos National Laboratory
+ *
+ *      Co-developed with
+ *              The Controls and Computing Group
+ *              Accelerator Systems Division
+ *              Advanced Photon Source
+ *              Argonne National Laboratory
+ *
+ * Modification Log:
+ * -----------------
+ *      ...
+ */
+
+#include	<vxWorks.h>
+#include	<types.h>
+#include	<stdioLib.h>
+#include	<wdLib.h>
+
+#include	<alarm.h>
+#include	<callback.h>
+#include	<cvtTable.h>
+#include	<dbDefs.h>
+#include	<dbAccess.h>
+#include	<recSup.h>
+#include	<devSup.h>
+#include	<link.h>
+#include	<aiRecord.h>
+
+/* Create the dset for devAiTestAsyn */
+long init_record();
+long read_ai();
+struct {
+	long		number;
+	DEVSUPFUN	report;
+	DEVSUPFUN	init;
+	DEVSUPFUN	init_record;
+	DEVSUPFUN	get_ioint_info;
+	DEVSUPFUN	read_ai;
+	DEVSUPFUN	special_linconv;
+}devAiTestAsyn={
+	6,
+	NULL,
+	NULL,
+	init_record,
+	NULL,
+	read_ai,
+	NULL};
+
+/* control block for callback*/
+struct callback {
+	void (*callback)();
+	int priority;
+	struct dbCommon *prec;
+	WDOG_ID wd_id;
+};
+
+void callbackRequest();
+
+static void myCallback(pcallback)
+    struct callback *pcallback;
+{
+    struct aiRecord *pai=(struct aiRecord *)(pcallback->prec);
+    struct rset     *prset=(struct rset *)(pai->rset);
+
+    dbScanLock(pai);
+    (*prset->process)(pai->pdba);
+    dbScanUnlock(pai);
+}
+    
+    
+
+static long init_record(pai)
+    struct aiRecord	*pai;
+{
+    char message[100];
+    struct callback *pcallback;
+
+    /* ai.inp must be a CONSTANT*/
+    switch (pai->inp.type) {
+    case (CONSTANT) :
+	pcallback = (struct callback *)(calloc(1,sizeof(struct callback)));
+	pai->dpvt = (caddr_t)pcallback;
+	pcallback->callback = myCallback;
+	pcallback->priority = priorityLow;
+	pcallback->prec = (struct dbCommon *)pai;
+	pcallback->wd_id = wdCreate();
+	pai->val = pai->inp.value.value;
+	pai->udf = FALSE;
+	break;
+    default :
+	strcpy(message,pai->name);
+	strcat(message,": devAiTestAsyn (init_record) Illegal INP field");
+	errMessage(S_db_badField,message);
+	return(S_db_badField);
+    }
+    return(0);
+}
+
+static long read_ai(pai)
+    struct aiRecord	*pai;
+{
+    char message[100];
+    long status,options,nRequest;
+    struct callback *pcallback=(struct callback *)(pai->dpvt);
+    int		wait_time;
+
+    /* ai.inp must be a CONSTANT*/
+    switch (pai->inp.type) {
+    case (CONSTANT) :
+	if(pai->pact) {
+		printf("%s Completed\n",pai->name);
+		return(2); /* don`t convert*/
+	} else {
+		wait_time = (int)(pai->disv * vxTicksPerSecond);
+		if(wait_time<=0) return(0);
+		printf("%s Starting asynchronous processing\n",pai->name);
+		wdStart(pcallback->wd_id,wait_time,callbackRequest,(int)pcallback);
+		return(1);
+	}
+    default :
+        if(recGblSetSevr(pai,SOFT_ALARM,VALID_ALARM)){
+		if(pai->stat!=SOFT_ALARM) {
+			strcpy(message,pai->name);
+			strcat(message,": devAiTestAsyn (read_ai) Illegal INP field");
+			errMessage(S_db_badField,message);
+		}
+	}
+    }
+    return(0);
+}