diff --git a/NEWS b/NEWS
index 5a3e3ef6..5c3b7f79 100644
--- a/NEWS
+++ b/NEWS
@@ -49,6 +49,7 @@ Changes in version 1.4.0:
 * Renamed ec_master module parameters main and backup to main_devices and
   backup_devices to avoid warnings of some compilers.
 * Added MODPROBE_FLAGS variable in start script and sysconfig file.
+* Implemented missing datagram types.
 
 -------------------------------------------------------------------------------
 
diff --git a/TODO b/TODO
index c444088a..a060b88d 100644
--- a/TODO
+++ b/TODO
@@ -22,7 +22,6 @@ Version 1.4.0:
 * Calculate expected working counter for domains.
 * Distributed clocks.
 * Support slaves, that don't support the LRW datagram, only LRD/LWR.
-* Implement all EtherCAT datagram types.
 
 Future issues:
 
diff --git a/master/datagram.c b/master/datagram.c
index adada8c2..0fe61111 100644
--- a/master/datagram.c
+++ b/master/datagram.c
@@ -65,7 +65,7 @@
 
 /** Constructor.
  */
-void ec_datagram_init(ec_datagram_t *datagram /**< EtherCAT datagram */)
+void ec_datagram_init(ec_datagram_t *datagram /**< EtherCAT datagram. */)
 {
     INIT_LIST_HEAD(&datagram->queue); // mark as unqueued
     datagram->type = EC_DATAGRAM_NONE;
@@ -90,7 +90,7 @@ void ec_datagram_init(ec_datagram_t *datagram /**< EtherCAT datagram */)
 
 /** Destructor.
  */
-void ec_datagram_clear(ec_datagram_t *datagram /**< EtherCAT datagram */)
+void ec_datagram_clear(ec_datagram_t *datagram /**< EtherCAT datagram. */)
 {
     if (datagram->data_origin == EC_ORIG_INTERNAL && datagram->data)
         kfree(datagram->data);
@@ -107,8 +107,9 @@ void ec_datagram_clear(ec_datagram_t *datagram /**< EtherCAT datagram */)
  *
  * \return 0 in case of success, else < 0
  */
-int ec_datagram_prealloc(ec_datagram_t *datagram, /**< EtherCAT datagram */
-        size_t size /**< New size in bytes */
+int ec_datagram_prealloc(
+        ec_datagram_t *datagram, /**< EtherCAT datagram. */
+        size_t size /**< New payload size in bytes. */
         )
 {
     if (datagram->data_origin == EC_ORIG_EXTERNAL
@@ -132,161 +133,284 @@ int ec_datagram_prealloc(ec_datagram_t *datagram, /**< EtherCAT datagram */
 
 /*****************************************************************************/
 
-/** Initializes an EtherCAT NPRD datagram.
- *
- * Node-adressed physical read.
- *
- * \return 0 in case of success, else < 0
- */
-int ec_datagram_nprd(ec_datagram_t *datagram,
-                     /**< EtherCAT datagram */
-                     uint16_t node_address,
-                     /**< configured station address */
-                     uint16_t offset,
-                     /**< physical memory address */
-                     size_t data_size
-                     /**< number of bytes to read */
-                     )
-{
-    if (unlikely(node_address == 0x0000))
-        EC_WARN("Using node address 0x0000!\n");
-
-    EC_FUNC_HEADER;
-    datagram->type = EC_DATAGRAM_NPRD;
-    EC_WRITE_U16(datagram->address, node_address);
-    EC_WRITE_U16(datagram->address + 2, offset);
-    EC_FUNC_FOOTER;
-}
-
-/*****************************************************************************/
-
-/** Initializes an EtherCAT NPWR datagram.
- *
- * Node-adressed physical write.
- *
- * \return 0 in case of success, else < 0
- */
-int ec_datagram_npwr(ec_datagram_t *datagram,
-                     /**< EtherCAT datagram */
-                     uint16_t node_address,
-                     /**< configured station address */
-                     uint16_t offset,
-                     /**< physical memory address */
-                     size_t data_size
-                     /**< number of bytes to write */
-                     )
-{
-    if (unlikely(node_address == 0x0000))
-        EC_WARN("Using node address 0x0000!\n");
-
-    EC_FUNC_HEADER;
-    datagram->type = EC_DATAGRAM_NPWR;
-    EC_WRITE_U16(datagram->address, node_address);
-    EC_WRITE_U16(datagram->address + 2, offset);
-    EC_FUNC_FOOTER;
-}
-
-/*****************************************************************************/
-
 /** Initializes an EtherCAT APRD datagram.
- *
- * Autoincrement physical read.
  *
  * \return 0 in case of success, else < 0
  */
-int ec_datagram_aprd(ec_datagram_t *datagram,
-                     /**< EtherCAT datagram */
-                     uint16_t ring_position,
-                     /**< auto-increment position */
-                     uint16_t offset,
-                     /**< physical memory address */
-                     size_t data_size
-                     /**< number of bytes to read */
-                     )
+int ec_datagram_aprd(
+        ec_datagram_t *datagram, /**< EtherCAT datagram. */
+        uint16_t ring_position, /**< Auto-increment address. */
+        uint16_t mem_address, /**< Physical memory address. */
+        size_t data_size /**< Number of bytes to read. */
+        )
 {
     EC_FUNC_HEADER;
     datagram->type = EC_DATAGRAM_APRD;
     EC_WRITE_S16(datagram->address, (int16_t) ring_position * (-1));
-    EC_WRITE_U16(datagram->address + 2, offset);
+    EC_WRITE_U16(datagram->address + 2, mem_address);
     EC_FUNC_FOOTER;
 }
 
 /*****************************************************************************/
 
 /** Initializes an EtherCAT APWR datagram.
- *
- * Autoincrement physical write.
  *
  * \return 0 in case of success, else < 0
  */
-int ec_datagram_apwr(ec_datagram_t *datagram,
-                     /**< EtherCAT datagram */
-                     uint16_t ring_position,
-                     /**< auto-increment position */
-                     uint16_t offset,
-                     /**< physical memory address */
-                     size_t data_size
-                     /**< number of bytes to write */
-                     )
+int ec_datagram_apwr(
+        ec_datagram_t *datagram, /**< EtherCAT datagram. */
+        uint16_t ring_position, /**< Auto-increment address. */
+        uint16_t mem_address, /**< Physical memory address. */
+        size_t data_size /**< Number of bytes to write. */
+        )
 {
     EC_FUNC_HEADER;
     datagram->type = EC_DATAGRAM_APWR;
     EC_WRITE_S16(datagram->address, (int16_t) ring_position * (-1));
-    EC_WRITE_U16(datagram->address + 2, offset);
+    EC_WRITE_U16(datagram->address + 2, mem_address);
+    EC_FUNC_FOOTER;
+}
+
+/*****************************************************************************/
+
+/** Initializes an EtherCAT APRW datagram.
+ *
+ * \return 0 in case of success, else < 0
+ */
+int ec_datagram_aprw(
+        ec_datagram_t *datagram, /**< EtherCAT datagram. */
+        uint16_t ring_position, /**< Auto-increment address. */
+        uint16_t mem_address, /**< Physical memory address. */
+        size_t data_size /**< Number of bytes to write. */
+        )
+{
+    EC_FUNC_HEADER;
+    datagram->type = EC_DATAGRAM_APRW;
+    EC_WRITE_S16(datagram->address, (int16_t) ring_position * (-1));
+    EC_WRITE_U16(datagram->address + 2, mem_address);
+    EC_FUNC_FOOTER;
+}
+
+/*****************************************************************************/
+
+/** Initializes an EtherCAT ARMW datagram.
+ *
+ * \return 0 in case of success, else < 0
+ */
+int ec_datagram_armw(
+        ec_datagram_t *datagram, /**< EtherCAT datagram. */
+        uint16_t ring_position, /**< Auto-increment address. */
+        uint16_t mem_address, /**< Physical memory address. */
+        size_t data_size /**< Number of bytes to read. */
+        )
+{
+    EC_FUNC_HEADER;
+    datagram->type = EC_DATAGRAM_ARMW;
+    EC_WRITE_S16(datagram->address, (int16_t) ring_position * (-1));
+    EC_WRITE_U16(datagram->address + 2, mem_address);
+    EC_FUNC_FOOTER;
+}
+
+/*****************************************************************************/
+
+/** Initializes an EtherCAT FPRD datagram.
+ *
+ * \return 0 in case of success, else < 0
+ */
+int ec_datagram_fprd(
+        ec_datagram_t *datagram, /**< EtherCAT datagram. */
+        uint16_t configured_address, /**< Configured station address. */
+        uint16_t mem_address, /**< Physical memory address. */
+        size_t data_size /**< Number of bytes to read. */
+        )
+{
+    if (unlikely(configured_address == 0x0000))
+        EC_WARN("Using configured station address 0x0000!\n");
+
+    EC_FUNC_HEADER;
+    datagram->type = EC_DATAGRAM_FPRD;
+    EC_WRITE_U16(datagram->address, configured_address);
+    EC_WRITE_U16(datagram->address + 2, mem_address);
+    EC_FUNC_FOOTER;
+}
+
+/*****************************************************************************/
+
+/** Initializes an EtherCAT FPWR datagram.
+ *
+ * \return 0 in case of success, else < 0
+ */
+int ec_datagram_fpwr(
+        ec_datagram_t *datagram, /**< EtherCAT datagram. */
+        uint16_t configured_address, /**< Configured station address. */
+        uint16_t mem_address, /**< Physical memory address. */
+        size_t data_size /**< Number of bytes to write. */
+        )
+{
+    if (unlikely(configured_address == 0x0000))
+        EC_WARN("Using configured station address 0x0000!\n");
+
+    EC_FUNC_HEADER;
+    datagram->type = EC_DATAGRAM_FPWR;
+    EC_WRITE_U16(datagram->address, configured_address);
+    EC_WRITE_U16(datagram->address + 2, mem_address);
+    EC_FUNC_FOOTER;
+}
+
+/*****************************************************************************/
+
+/** Initializes an EtherCAT FPRW datagram.
+ *
+ * \return 0 in case of success, else < 0
+ */
+int ec_datagram_fprw(
+        ec_datagram_t *datagram, /**< EtherCAT datagram. */
+        uint16_t configured_address, /**< Configured station address. */
+        uint16_t mem_address, /**< Physical memory address. */
+        size_t data_size /**< Number of bytes to write. */
+        )
+{
+    if (unlikely(configured_address == 0x0000))
+        EC_WARN("Using configured station address 0x0000!\n");
+
+    EC_FUNC_HEADER;
+    datagram->type = EC_DATAGRAM_FPRW;
+    EC_WRITE_U16(datagram->address, configured_address);
+    EC_WRITE_U16(datagram->address + 2, mem_address);
+    EC_FUNC_FOOTER;
+}
+
+/*****************************************************************************/
+
+/** Initializes an EtherCAT FRMW datagram.
+ *
+ * \return 0 in case of success, else < 0
+ */
+int ec_datagram_frmw(
+        ec_datagram_t *datagram, /**< EtherCAT datagram. */
+        uint16_t configured_address, /**< Configured station address. */
+        uint16_t mem_address, /**< Physical memory address. */
+        size_t data_size /**< Number of bytes to write. */
+        )
+{
+    if (unlikely(configured_address == 0x0000))
+        EC_WARN("Using configured station address 0x0000!\n");
+
+    EC_FUNC_HEADER;
+    datagram->type = EC_DATAGRAM_FRMW;
+    EC_WRITE_U16(datagram->address, configured_address);
+    EC_WRITE_U16(datagram->address + 2, mem_address);
     EC_FUNC_FOOTER;
 }
 
 /*****************************************************************************/
 
 /** Initializes an EtherCAT BRD datagram.
- *
- * Broadcast read.
  *
  * \return 0 in case of success, else < 0
  */
-int ec_datagram_brd(ec_datagram_t *datagram,
-                    /**< EtherCAT datagram */
-                    uint16_t offset,
-                    /**< physical memory address */
-                    size_t data_size
-                    /**< number of bytes to read */
-                    )
+int ec_datagram_brd(
+        ec_datagram_t *datagram, /**< EtherCAT datagram. */
+        uint16_t mem_address, /**< Physical memory address. */
+        size_t data_size /**< Number of bytes to read. */
+        )
 {
     EC_FUNC_HEADER;
     datagram->type = EC_DATAGRAM_BRD;
     EC_WRITE_U16(datagram->address, 0x0000);
-    EC_WRITE_U16(datagram->address + 2, offset);
+    EC_WRITE_U16(datagram->address + 2, mem_address);
     EC_FUNC_FOOTER;
 }
 
 /*****************************************************************************/
 
 /** Initializes an EtherCAT BWR datagram.
- *
- * Broadcast write.
  *
  * \return 0 in case of success, else < 0
  */
-int ec_datagram_bwr(ec_datagram_t *datagram,
-                    /**< EtherCAT datagram */
-                    uint16_t offset,
-                    /**< physical memory address */
-                    size_t data_size
-                    /**< number of bytes to write */
-                    )
+int ec_datagram_bwr(
+        ec_datagram_t *datagram, /**< EtherCAT datagram. */
+        uint16_t mem_address, /**< Physical memory address. */
+        size_t data_size /**< Number of bytes to write. */
+        )
 {
     EC_FUNC_HEADER;
     datagram->type = EC_DATAGRAM_BWR;
     EC_WRITE_U16(datagram->address, 0x0000);
-    EC_WRITE_U16(datagram->address + 2, offset);
+    EC_WRITE_U16(datagram->address + 2, mem_address);
+    EC_FUNC_FOOTER;
+}
+
+/*****************************************************************************/
+
+/** Initializes an EtherCAT BRW datagram.
+ *
+ * \return 0 in case of success, else < 0
+ */
+int ec_datagram_brw(
+        ec_datagram_t *datagram, /**< EtherCAT datagram. */
+        uint16_t mem_address, /**< Physical memory address. */
+        size_t data_size /**< Number of bytes to write. */
+        )
+{
+    EC_FUNC_HEADER;
+    datagram->type = EC_DATAGRAM_BRW;
+    EC_WRITE_U16(datagram->address, 0x0000);
+    EC_WRITE_U16(datagram->address + 2, mem_address);
+    EC_FUNC_FOOTER;
+}
+
+/*****************************************************************************/
+
+/** Initializes an EtherCAT LRD datagram.
+ *
+ * \attention It is assumed, that the external memory is at least \a data_size
+ *            bytes large.
+ *
+ * \return 0 in case of success, else < 0
+ */
+int ec_datagram_lrd(
+        ec_datagram_t *datagram, /**< EtherCAT datagram. */
+        uint32_t offset, /**< Logical address. */
+        size_t data_size, /**< Number of bytes to read/write. */
+        uint8_t *external_memory /**< Pointer to the memory to use. */
+        )
+{
+    datagram->data = external_memory;
+    datagram->data_origin = EC_ORIG_EXTERNAL;
+    EC_FUNC_HEADER;
+    datagram->type = EC_DATAGRAM_LRD;
+    EC_WRITE_U32(datagram->address, offset);
+    EC_FUNC_FOOTER;
+}
+
+/*****************************************************************************/
+
+/** Initializes an EtherCAT LWR datagram.
+ *
+ * \attention It is assumed, that the external memory is at least \a data_size
+ *            bytes large.
+ *
+ * \return 0 in case of success, else < 0
+ */
+int ec_datagram_lwr(
+        ec_datagram_t *datagram, /**< EtherCAT datagram. */
+        uint32_t offset, /**< Logical address. */
+        size_t data_size, /**< Number of bytes to read/write. */
+        uint8_t *external_memory /**< Pointer to the memory to use. */
+        )
+{
+    datagram->data = external_memory;
+    datagram->data_origin = EC_ORIG_EXTERNAL;
+    EC_FUNC_HEADER;
+    datagram->type = EC_DATAGRAM_LWR;
+    EC_WRITE_U32(datagram->address, offset);
     EC_FUNC_FOOTER;
 }
 
 /*****************************************************************************/
 
 /** Initializes an EtherCAT LRW datagram.
- *
- * Logical read write.
  *
  * \attention It is assumed, that the external memory is at least \a data_size
  *            bytes large.
@@ -294,7 +418,7 @@ int ec_datagram_bwr(ec_datagram_t *datagram,
  * \return 0 in case of success, else < 0
  */
 int ec_datagram_lrw(
-        ec_datagram_t *datagram, /**< EtherCAT datagram */
+        ec_datagram_t *datagram, /**< EtherCAT datagram. */
         uint32_t offset, /**< Logical address. */
         size_t data_size, /**< Number of bytes to read/write. */
         uint8_t *external_memory /**< Pointer to the memory to use. */
diff --git a/master/datagram.h b/master/datagram.h
index 3dd93ae1..41b6bd1a 100644
--- a/master/datagram.h
+++ b/master/datagram.h
@@ -49,7 +49,7 @@
 
 /*****************************************************************************/
 
-/** size of the datagram description string */
+/** Size of the datagram description string. */
 #define EC_DATAGRAM_NAME_SIZE 20
 
 /*****************************************************************************/
@@ -58,13 +58,22 @@
  */
 typedef enum {
     EC_DATAGRAM_NONE = 0x00, /**< Dummy. */
-    EC_DATAGRAM_APRD = 0x01, /**< Auto-increment physical read. */
-    EC_DATAGRAM_APWR = 0x02, /**< Auto-increment physical write. */
-    EC_DATAGRAM_NPRD = 0x04, /**< Node-addressed physical read. */
-    EC_DATAGRAM_NPWR = 0x05, /**< Node-addressed physical write. */
-    EC_DATAGRAM_BRD  = 0x07, /**< Broadcast read. */
-    EC_DATAGRAM_BWR  = 0x08, /**< Broadcast write. */
-    EC_DATAGRAM_LRW  = 0x0C  /**< Logical read/write. */
+    EC_DATAGRAM_APRD = 0x01, /**< Auto Increment Physical Read. */
+    EC_DATAGRAM_APWR = 0x02, /**< Auto Increment Physical Write. */
+    EC_DATAGRAM_APRW = 0x03, /**< Auto Increment Physical ReadWrite. */
+    EC_DATAGRAM_FPRD = 0x04, /**< Configured Address Physical Read. */
+    EC_DATAGRAM_FPWR = 0x05, /**< Configured Address Physical Write. */
+    EC_DATAGRAM_FPRW = 0x06, /**< Configured Address Physical ReadWrite. */
+    EC_DATAGRAM_BRD  = 0x07, /**< Broadcast Read. */
+    EC_DATAGRAM_BWR  = 0x08, /**< Broadcast Write. */
+    EC_DATAGRAM_BRW  = 0x09, /**< Broadcast ReadWrite. */
+    EC_DATAGRAM_LRD  = 0x0A, /**< Logical Read. */
+    EC_DATAGRAM_LWR  = 0x0B, /**< Logical Write. */
+    EC_DATAGRAM_LRW  = 0x0C, /**< Logical ReadWrite. */
+    EC_DATAGRAM_ARMW = 0x0D, /**< Auto Increment Physical Read Multiple
+                               Write.  */
+    EC_DATAGRAM_FRMW = 0x0E, /**< Configured Address Physical Read Multiple
+                               Write. */
 } ec_datagram_type_t;
 
 /*****************************************************************************/
@@ -113,12 +122,19 @@ void ec_datagram_init(ec_datagram_t *);
 void ec_datagram_clear(ec_datagram_t *);
 int ec_datagram_prealloc(ec_datagram_t *, size_t);
 
-int ec_datagram_nprd(ec_datagram_t *, uint16_t, uint16_t, size_t);
-int ec_datagram_npwr(ec_datagram_t *, uint16_t, uint16_t, size_t);
 int ec_datagram_aprd(ec_datagram_t *, uint16_t, uint16_t, size_t);
 int ec_datagram_apwr(ec_datagram_t *, uint16_t, uint16_t, size_t);
+int ec_datagram_aprw(ec_datagram_t *, uint16_t, uint16_t, size_t);
+int ec_datagram_armw(ec_datagram_t *, uint16_t, uint16_t, size_t);
+int ec_datagram_fprd(ec_datagram_t *, uint16_t, uint16_t, size_t);
+int ec_datagram_fpwr(ec_datagram_t *, uint16_t, uint16_t, size_t);
+int ec_datagram_fprw(ec_datagram_t *, uint16_t, uint16_t, size_t);
+int ec_datagram_frmw(ec_datagram_t *, uint16_t, uint16_t, size_t);
 int ec_datagram_brd(ec_datagram_t *, uint16_t, size_t);
 int ec_datagram_bwr(ec_datagram_t *, uint16_t, size_t);
+int ec_datagram_brw(ec_datagram_t *, uint16_t, size_t);
+int ec_datagram_lrd(ec_datagram_t *, uint32_t, size_t, uint8_t *);
+int ec_datagram_lwr(ec_datagram_t *, uint32_t, size_t, uint8_t *);
 int ec_datagram_lrw(ec_datagram_t *, uint32_t, size_t, uint8_t *);
 
 void ec_datagram_print_wc_error(const ec_datagram_t *);
diff --git a/master/fsm_change.c b/master/fsm_change.c
index adabedc3..47a982e5 100644
--- a/master/fsm_change.c
+++ b/master/fsm_change.c
@@ -157,7 +157,7 @@ void ec_fsm_change_state_start(ec_fsm_change_t *fsm
     fsm->old_state = fsm->slave->current_state;
 
     // write new state to slave
-    ec_datagram_npwr(datagram, slave->station_address, 0x0120, 2);
+    ec_datagram_fpwr(datagram, slave->station_address, 0x0120, 2);
     EC_WRITE_U16(datagram->data, fsm->requested_state);
     fsm->retries = EC_FSM_RETRIES;
     fsm->state = ec_fsm_change_state_check;
@@ -203,7 +203,7 @@ void ec_fsm_change_state_check(ec_fsm_change_t *fsm
         }
 
         // repeat writing new state to slave
-        ec_datagram_npwr(datagram, slave->station_address, 0x0120, 2);
+        ec_datagram_fpwr(datagram, slave->station_address, 0x0120, 2);
         EC_WRITE_U16(datagram->data, fsm->requested_state);
         fsm->retries = EC_FSM_RETRIES;
         return;
@@ -222,7 +222,7 @@ void ec_fsm_change_state_check(ec_fsm_change_t *fsm
     fsm->take_time = 1;
 
     // read AL status from slave
-    ec_datagram_nprd(datagram, slave->station_address, 0x0130, 2);
+    ec_datagram_fprd(datagram, slave->station_address, 0x0130, 2);
     fsm->retries = EC_FSM_RETRIES;
     fsm->spontaneous_change = 0;
     fsm->state = ec_fsm_change_state_status;
@@ -298,7 +298,7 @@ void ec_fsm_change_state_status(ec_fsm_change_t *fsm
         EC_ERR("Failed to set %s state, slave %i refused state change (%s).\n",
                req_state, slave->ring_position, cur_state);
         // fetch AL status error code
-        ec_datagram_nprd(datagram, slave->station_address, 0x0134, 2);
+        ec_datagram_fprd(datagram, slave->station_address, 0x0134, 2);
         fsm->retries = EC_FSM_RETRIES;
         fsm->state = ec_fsm_change_state_code;
         return;
@@ -318,7 +318,7 @@ void ec_fsm_change_state_status(ec_fsm_change_t *fsm
 
  check_again:
     // no timeout yet. check again
-    ec_datagram_nprd(datagram, slave->station_address, 0x0130, 2);
+    ec_datagram_fprd(datagram, slave->station_address, 0x0130, 2);
     fsm->retries = EC_FSM_RETRIES;
 }
 
@@ -417,7 +417,7 @@ void ec_fsm_change_state_start_ack(ec_fsm_change_t *fsm
     ec_slave_t *slave = fsm->slave;
     ec_datagram_t *datagram = fsm->datagram;
 
-    ec_datagram_npwr(datagram, slave->station_address, 0x0120, 2);
+    ec_datagram_fpwr(datagram, slave->station_address, 0x0120, 2);
     EC_WRITE_U16(datagram->data, slave->current_state);
     fsm->retries = EC_FSM_RETRIES;
     fsm->state = ec_fsm_change_state_ack;
@@ -456,7 +456,7 @@ void ec_fsm_change_state_ack(ec_fsm_change_t *fsm /**< finite state machine */)
     fsm->take_time = 1;
 
     // read new AL status
-    ec_datagram_nprd(datagram, slave->station_address, 0x0130, 2);
+    ec_datagram_fprd(datagram, slave->station_address, 0x0130, 2);
     fsm->retries = EC_FSM_RETRIES;
     fsm->state = ec_fsm_change_state_check_ack;
 }
@@ -524,7 +524,7 @@ void ec_fsm_change_state_check_ack(ec_fsm_change_t *fsm
     }
 
     // reread new AL status
-    ec_datagram_nprd(datagram, slave->station_address, 0x0130, 2);
+    ec_datagram_fprd(datagram, slave->station_address, 0x0130, 2);
     fsm->retries = EC_FSM_RETRIES;
 }
 
diff --git a/master/fsm_master.c b/master/fsm_master.c
index 411336be..a9cbaa6c 100644
--- a/master/fsm_master.c
+++ b/master/fsm_master.c
@@ -297,7 +297,7 @@ void ec_fsm_master_state_broadcast(ec_fsm_master_t *fsm /**< master state machin
 
     // fetch state from each slave
     fsm->slave = list_entry(master->slaves.next, ec_slave_t, list);
-    ec_datagram_nprd(fsm->datagram, fsm->slave->station_address, 0x0130, 2);
+    ec_datagram_fprd(fsm->datagram, fsm->slave->station_address, 0x0130, 2);
     fsm->retries = EC_FSM_RETRIES;
     fsm->state = ec_fsm_master_state_read_states;
 }
@@ -347,7 +347,7 @@ int ec_fsm_master_action_process_eeprom(
         fsm->eeprom_request = request;
         fsm->eeprom_index = 0;
         ec_fsm_sii_write(&fsm->fsm_sii, request->slave, request->word_offset,
-                request->data, EC_FSM_SII_NODE);
+                request->data, EC_FSM_SII_USE_CONFIGURED_ADDRESS);
         fsm->state = ec_fsm_master_state_write_eeprom;
         fsm->state(fsm); // execute immediately
         return 1;
@@ -572,7 +572,7 @@ void ec_fsm_master_action_next_slave_state(ec_fsm_master_t *fsm
         // process next slave
         fsm->idle = 1;
         fsm->slave = list_entry(slave->list.next, ec_slave_t, list);
-        ec_datagram_nprd(fsm->datagram, fsm->slave->station_address,
+        ec_datagram_fprd(fsm->datagram, fsm->slave->station_address,
                          0x0130, 2);
         fsm->retries = EC_FSM_RETRIES;
         fsm->state = ec_fsm_master_state_read_states;
@@ -592,7 +592,8 @@ void ec_fsm_master_action_next_slave_state(ec_fsm_master_t *fsm
             fsm->idle = 0;
             fsm->slave = list_entry(master->slaves.next, ec_slave_t, list);
             fsm->state = ec_fsm_master_state_validate_vendor;
-            ec_fsm_sii_read(&fsm->fsm_sii, slave, 0x0008, EC_FSM_SII_POSITION);
+            ec_fsm_sii_read(&fsm->fsm_sii, slave, 0x0008,
+                    EC_FSM_SII_USE_INCREMENT_ADDRESS);
             ec_fsm_sii_exec(&fsm->fsm_sii); // execute immediately
             return;
         }
@@ -701,7 +702,8 @@ void ec_fsm_master_state_validate_vendor(ec_fsm_master_t *fsm /**< master state
 
     // vendor ID is ok. check product code.
     fsm->state = ec_fsm_master_state_validate_product;
-    ec_fsm_sii_read(&fsm->fsm_sii, slave, 0x000A, EC_FSM_SII_POSITION);
+    ec_fsm_sii_read(&fsm->fsm_sii, slave, 0x000A,
+            EC_FSM_SII_USE_INCREMENT_ADDRESS);
     ec_fsm_sii_exec(&fsm->fsm_sii); // execute immediately
 }
 
@@ -778,7 +780,8 @@ void ec_fsm_master_state_validate_product(ec_fsm_master_t *fsm /**< master state
     // validate next slave
     fsm->slave = list_entry(fsm->slave->list.next, ec_slave_t, list);
     fsm->state = ec_fsm_master_state_validate_vendor;
-    ec_fsm_sii_read(&fsm->fsm_sii, slave, 0x0008, EC_FSM_SII_POSITION);
+    ec_fsm_sii_read(&fsm->fsm_sii, slave, 0x0008,
+            EC_FSM_SII_USE_INCREMENT_ADDRESS);
     ec_fsm_sii_exec(&fsm->fsm_sii); // execute immediately
 }
 
@@ -980,7 +983,7 @@ void ec_fsm_master_state_write_eeprom(
         ec_fsm_sii_write(&fsm->fsm_sii, slave,
                 request->word_offset + fsm->eeprom_index,
                 request->data + fsm->eeprom_index * 2,
-                EC_FSM_SII_NODE);
+                EC_FSM_SII_USE_CONFIGURED_ADDRESS);
         ec_fsm_sii_exec(&fsm->fsm_sii); // execute immediately
         return;
     }
diff --git a/master/fsm_sii.c b/master/fsm_sii.c
index 26c4af90..cdbb0cc3 100644
--- a/master/fsm_sii.c
+++ b/master/fsm_sii.c
@@ -172,11 +172,11 @@ void ec_fsm_sii_state_start_reading(
 
     // initiate read operation
     switch (fsm->mode) {
-        case EC_FSM_SII_POSITION:
+        case EC_FSM_SII_USE_INCREMENT_ADDRESS:
             ec_datagram_apwr(datagram, fsm->slave->ring_position, 0x502, 4);
             break;
-        case EC_FSM_SII_NODE:
-            ec_datagram_npwr(datagram, fsm->slave->station_address, 0x502, 4);
+        case EC_FSM_SII_USE_CONFIGURED_ADDRESS:
+            ec_datagram_fpwr(datagram, fsm->slave->station_address, 0x502, 4);
             break;
     }
 
@@ -230,11 +230,11 @@ void ec_fsm_sii_state_read_check(
 
     // issue check/fetch datagram
     switch (fsm->mode) {
-        case EC_FSM_SII_POSITION:
+        case EC_FSM_SII_USE_INCREMENT_ADDRESS:
             ec_datagram_aprd(datagram, fsm->slave->ring_position, 0x502, 10);
             break;
-        case EC_FSM_SII_NODE:
-            ec_datagram_nprd(datagram, fsm->slave->station_address, 0x502, 10);
+        case EC_FSM_SII_USE_CONFIGURED_ADDRESS:
+            ec_datagram_fprd(datagram, fsm->slave->station_address, 0x502, 10);
             break;
     }
 
@@ -324,7 +324,7 @@ void ec_fsm_sii_state_start_writing(
     ec_datagram_t *datagram = fsm->datagram;
 
     // initiate write operation
-    ec_datagram_npwr(datagram, fsm->slave->station_address, 0x502, 8);
+    ec_datagram_fpwr(datagram, fsm->slave->station_address, 0x502, 8);
     EC_WRITE_U8 (datagram->data,     0x81); // two address octets
 											// + enable write access
     EC_WRITE_U8 (datagram->data + 1, 0x02); // request write operation
@@ -376,7 +376,7 @@ void ec_fsm_sii_state_write_check(
     fsm->check_once_more = 1;
 
     // issue check datagram
-    ec_datagram_nprd(datagram, fsm->slave->station_address, 0x502, 2);
+    ec_datagram_fprd(datagram, fsm->slave->station_address, 0x502, 2);
     fsm->retries = EC_FSM_RETRIES;
     fsm->state = ec_fsm_sii_state_write_check2;
 }
diff --git a/master/fsm_sii.h b/master/fsm_sii.h
index 5721f7c7..0b2af101 100644
--- a/master/fsm_sii.h
+++ b/master/fsm_sii.h
@@ -48,15 +48,12 @@
 
 /*****************************************************************************/
 
-/**
- * SII access addressing mode.
+/** SII access addressing mode.
  */
-typedef enum
-{
-    EC_FSM_SII_POSITION,
-    EC_FSM_SII_NODE
-}
-ec_fsm_sii_addressing_t;
+typedef enum {
+    EC_FSM_SII_USE_INCREMENT_ADDRESS, /**< Use auto-increment addressing. */
+    EC_FSM_SII_USE_CONFIGURED_ADDRESS /**< Use configured addresses. */
+} ec_fsm_sii_addressing_t;
 
 /*****************************************************************************/
 
diff --git a/master/fsm_slave.c b/master/fsm_slave.c
index 2a6204b0..ba073897 100644
--- a/master/fsm_slave.c
+++ b/master/fsm_slave.c
@@ -232,7 +232,7 @@ void ec_fsm_slave_scan_state_address(ec_fsm_slave_t *fsm /**< slave state machin
     }
 
     // Read AL state
-    ec_datagram_nprd(datagram, fsm->slave->station_address, 0x0130, 2);
+    ec_datagram_fprd(datagram, fsm->slave->station_address, 0x0130, 2);
     fsm->retries = EC_FSM_RETRIES;
     fsm->state = ec_fsm_slave_scan_state_state;
 }
@@ -279,7 +279,7 @@ void ec_fsm_slave_scan_state_state(
     }
 
     // read base data
-    ec_datagram_nprd(datagram, fsm->slave->station_address, 0x0000, 6);
+    ec_datagram_fprd(datagram, fsm->slave->station_address, 0x0000, 6);
     fsm->retries = EC_FSM_RETRIES;
     fsm->state = ec_fsm_slave_scan_state_base;
 }
@@ -324,7 +324,7 @@ void ec_fsm_slave_scan_state_base(ec_fsm_slave_t *fsm /**< slave state machine *
         slave->base_fmmu_count = EC_MAX_FMMUS;
 
     // read data link status
-    ec_datagram_nprd(datagram, slave->station_address, 0x0110, 2);
+    ec_datagram_fprd(datagram, slave->station_address, 0x0110, 2);
     fsm->retries = EC_FSM_RETRIES;
     fsm->state = ec_fsm_slave_scan_state_datalink;
 }
@@ -372,7 +372,8 @@ void ec_fsm_slave_scan_state_datalink(ec_fsm_slave_t *fsm /**< slave state machi
     // Start fetching EEPROM size
 
     fsm->sii_offset = EC_FIRST_EEPROM_CATEGORY_OFFSET; // first category header
-    ec_fsm_sii_read(&fsm->fsm_sii, slave, fsm->sii_offset, EC_FSM_SII_NODE);
+    ec_fsm_sii_read(&fsm->fsm_sii, slave, fsm->sii_offset,
+            EC_FSM_SII_USE_CONFIGURED_ADDRESS);
     fsm->state = ec_fsm_slave_scan_state_eeprom_size;
     fsm->state(fsm); // execute state immediately
 }
@@ -413,7 +414,7 @@ void ec_fsm_slave_scan_state_eeprom_size(ec_fsm_slave_t *fsm /**< slave state ma
         }
         fsm->sii_offset = next_offset;
         ec_fsm_sii_read(&fsm->fsm_sii, slave, fsm->sii_offset,
-                        EC_FSM_SII_NODE);
+                        EC_FSM_SII_USE_CONFIGURED_ADDRESS);
         ec_fsm_sii_exec(&fsm->fsm_sii); // execute state immediately
         return;
     }
@@ -441,7 +442,8 @@ alloc_eeprom:
 
     fsm->state = ec_fsm_slave_scan_state_eeprom_data;
     fsm->sii_offset = 0x0000;
-    ec_fsm_sii_read(&fsm->fsm_sii, slave, fsm->sii_offset, EC_FSM_SII_NODE);
+    ec_fsm_sii_read(&fsm->fsm_sii, slave, fsm->sii_offset,
+            EC_FSM_SII_USE_CONFIGURED_ADDRESS);
     ec_fsm_sii_exec(&fsm->fsm_sii); // execute state immediately
 }
 
@@ -481,7 +483,7 @@ void ec_fsm_slave_scan_state_eeprom_data(ec_fsm_slave_t *fsm /**< slave state ma
         // fetch the next 2 words
         fsm->sii_offset += 2;
         ec_fsm_sii_read(&fsm->fsm_sii, slave, fsm->sii_offset,
-                        EC_FSM_SII_NODE);
+                        EC_FSM_SII_USE_CONFIGURED_ADDRESS);
         ec_fsm_sii_exec(&fsm->fsm_sii); // execute state immediately
         return;
     }
@@ -660,7 +662,7 @@ void ec_fsm_slave_conf_state_init(ec_fsm_slave_t *fsm /**< slave state machine *
                slave->ring_position);
 
     // clear FMMU configurations
-    ec_datagram_npwr(datagram, slave->station_address,
+    ec_datagram_fpwr(datagram, slave->station_address,
             0x0600, EC_FMMU_PAGE_SIZE * slave->base_fmmu_count);
     memset(datagram->data, 0x00, EC_FMMU_PAGE_SIZE * slave->base_fmmu_count);
     fsm->retries = EC_FSM_RETRIES;
@@ -740,7 +742,7 @@ void ec_fsm_slave_conf_enter_mbox_sync(
     }
 
     if (slave->sii_sync_count >= 2) { // mailbox configuration provided
-        ec_datagram_npwr(datagram, slave->station_address, 0x0800,
+        ec_datagram_fpwr(datagram, slave->station_address, 0x0800,
                 EC_SYNC_PAGE_SIZE * slave->sii_sync_count);
         memset(datagram->data, 0x00,
                 EC_SYNC_PAGE_SIZE * slave->sii_sync_count);
@@ -757,7 +759,7 @@ void ec_fsm_slave_conf_enter_mbox_sync(
                     " mailbox sync manager configurations.\n",
                     slave->ring_position);
 
-        ec_datagram_npwr(datagram, slave->station_address, 0x0800,
+        ec_datagram_fpwr(datagram, slave->station_address, 0x0800,
                 EC_SYNC_PAGE_SIZE * 2);
         memset(datagram->data, 0x00, EC_SYNC_PAGE_SIZE * 2);
 
@@ -1024,7 +1026,7 @@ void ec_fsm_slave_conf_enter_pdo_sync(
     num_syncs = slave->sii_sync_count - offset;
 
     // configure sync managers for process data
-    ec_datagram_npwr(datagram, slave->station_address,
+    ec_datagram_fpwr(datagram, slave->station_address,
             0x0800 + EC_SYNC_PAGE_SIZE * offset,
             EC_SYNC_PAGE_SIZE * num_syncs);
     memset(datagram->data, 0x00, EC_SYNC_PAGE_SIZE * num_syncs);
@@ -1094,7 +1096,7 @@ void ec_fsm_slave_conf_enter_fmmu(ec_fsm_slave_t *fsm /**< slave state machine *
     }
 
     // configure FMMUs
-    ec_datagram_npwr(datagram, slave->station_address,
+    ec_datagram_fpwr(datagram, slave->station_address,
                      0x0600, EC_FMMU_PAGE_SIZE * slave->base_fmmu_count);
     memset(datagram->data, 0x00, EC_FMMU_PAGE_SIZE * slave->base_fmmu_count);
     for (i = 0; i < slave->config->used_fmmus; i++) {
diff --git a/master/mailbox.c b/master/mailbox.c
index 1b561947..feb02a45 100644
--- a/master/mailbox.c
+++ b/master/mailbox.c
@@ -72,7 +72,7 @@ uint8_t *ec_slave_mbox_prepare_send(const ec_slave_t *slave, /**< slave */
         return NULL;
     }
 
-    if (ec_datagram_npwr(datagram, slave->station_address,
+    if (ec_datagram_fpwr(datagram, slave->station_address,
                          slave->sii_rx_mailbox_offset,
                          slave->sii_rx_mailbox_size))
         return NULL;
@@ -97,7 +97,7 @@ int ec_slave_mbox_prepare_check(const ec_slave_t *slave, /**< slave */
                                 ec_datagram_t *datagram /**< datagram */
                                 )
 {
-    if (ec_datagram_nprd(datagram, slave->station_address, 0x808, 8))
+    if (ec_datagram_fprd(datagram, slave->station_address, 0x808, 8))
         return -1;
 
     return 0;
@@ -126,7 +126,7 @@ int ec_slave_mbox_prepare_fetch(const ec_slave_t *slave, /**< slave */
                                 ec_datagram_t *datagram /**< datagram */
                                 )
 {
-    if (ec_datagram_nprd(datagram, slave->station_address,
+    if (ec_datagram_fprd(datagram, slave->station_address,
                          slave->sii_tx_mailbox_offset,
                          slave->sii_tx_mailbox_size)) return -1;
     return 0;