diff --git a/modules/database/src/ioc/db/dbConvertFast.h b/modules/database/src/ioc/db/dbConvertFast.h
index 0980b6b198..470cedbdd9 100644
--- a/modules/database/src/ioc/db/dbConvertFast.h
+++ b/modules/database/src/ioc/db/dbConvertFast.h
@@ -7,7 +7,20 @@
 * EPICS Base is distributed subject to a Software License Agreement found
 * in file LICENSE that is included with this distribution.
 \*************************************************************************/
-/* dbConvertFast.h */
+/** @file dbConvertFast.h
+ *  @brief Data conversion for scalar values
+ *
+ * The typedef FASTCONVERTFUNC is defined in link.h as:
+ * @code
+ *   long convert(const void *from, void *to, const struct dbAddr *paddr);
+ * @endcode
+ *
+ * The arrays declared here provide pointers to the fast conversion
+ * routine where the first array index is the data type for the first
+ * "from" pointer arg, and the second array index is the data type for
+ * the second "to" pointer arg. The array index values are a subset of
+ * the DBF_ enum values defined in dbFldTypes.h
+ */
 
 #ifndef INCdbConvertFasth
 #define INCdbConvertFasth
@@ -20,10 +33,12 @@
 extern "C" {
 #endif
 
-/* typedef FASTCONVERTFUNC is now defined in link.h */
-
-DBCORE_API extern FASTCONVERTFUNC dbFastGetConvertRoutine[DBF_DEVICE+1][DBR_ENUM+1];
-DBCORE_API extern FASTCONVERTFUNC dbFastPutConvertRoutine[DBR_ENUM+1][DBF_DEVICE+1];
+/** Function pointers for get conversions */
+DBCORE_API extern const FASTCONVERTFUNC
+    dbFastGetConvertRoutine[DBF_DEVICE+1][DBR_ENUM+1];
+/** Function pointers for put conversions */
+DBCORE_API extern const FASTCONVERTFUNC
+    dbFastPutConvertRoutine[DBR_ENUM+1][DBF_DEVICE+1];
 
 #ifdef __cplusplus
 }
diff --git a/modules/database/src/ioc/db/dbFastLinkConv.c b/modules/database/src/ioc/db/dbFastLinkConv.c
index fc229605ff..7d463d4d1a 100644
--- a/modules/database/src/ioc/db/dbFastLinkConv.c
+++ b/modules/database/src/ioc/db/dbFastLinkConv.c
@@ -1639,7 +1639,7 @@ static long cvt_device_st(const void *f, void *t, const dbAddr *paddr)
  *  NULL implies the conversion is not supported.
  */
 
-FASTCONVERTFUNC dbFastGetConvertRoutine[DBF_DEVICE+1][DBR_ENUM+1] = {
+FASTCONVERTFUNC const dbFastGetConvertRoutine[DBF_DEVICE+1][DBR_ENUM+1] = {
 
  /* Convert DBF_STRING to ... */
 { cvt_st_st, cvt_st_c, cvt_st_uc, cvt_st_s, cvt_st_us, cvt_st_l, cvt_st_ul, cvt_st_q, cvt_st_uq, cvt_st_f, cvt_st_d, cvt_st_e },
@@ -1695,7 +1695,7 @@ FASTCONVERTFUNC dbFastGetConvertRoutine[DBF_DEVICE+1][DBR_ENUM+1] = {
  *  NULL implies the conversion is not supported.
  */
 
-FASTCONVERTFUNC dbFastPutConvertRoutine[DBR_ENUM+1][DBF_DEVICE+1] = {
+FASTCONVERTFUNC const dbFastPutConvertRoutine[DBR_ENUM+1][DBF_DEVICE+1] = {
 
  /* Convert DBR_STRING to ... */
 { cvt_st_st, cvt_st_c, cvt_st_uc, cvt_st_s, cvt_st_us, cvt_st_l, cvt_st_ul, cvt_st_q, cvt_st_uq, cvt_st_f, cvt_st_d, cvt_st_e, cvt_st_menu, cvt_st_device},