diff --git a/TODO b/TODO
index 9d4edf0c..e7b0ac42 100644
--- a/TODO
+++ b/TODO
@@ -8,8 +8,6 @@ $Id$
 
 Version 1.4.0:
 
-* Realtime interface changes:
-    - SDO access.
 * Mailbox handler
 * READMEs for examples.
 * Remove get_cycles() calls and references to cpu_khz to increase
diff --git a/master/fsm_coe.c b/master/fsm_coe.c
index 34f3a053..86d3071f 100644
--- a/master/fsm_coe.c
+++ b/master/fsm_coe.c
@@ -180,10 +180,10 @@ void ec_fsm_coe_dictionary(ec_fsm_coe_t *fsm, /**< finite state machine */
 /*****************************************************************************/
 
 /**
-   Starts to download an Sdo to a slave.
+   Starts to transfer an Sdo to/from a slave.
 */
 
-void ec_fsm_coe_download(
+void ec_fsm_coe_transfer(
         ec_fsm_coe_t *fsm, /**< State machine. */
         ec_slave_t *slave, /**< EtherCAT slave. */
         ec_sdo_request_t *request /**< Sdo request. */
@@ -191,23 +191,10 @@ void ec_fsm_coe_download(
 {
     fsm->slave = slave;
     fsm->request = request;
-    fsm->state = ec_fsm_coe_down_start;
-}
-
-/*****************************************************************************/
-
-/**
-   Starts to upload an Sdo from a slave.
-*/
-
-void ec_fsm_coe_upload(ec_fsm_coe_t *fsm, /**< finite state machine */
-                       ec_slave_t *slave, /**< EtherCAT slave */
-                       ec_sdo_request_t *request /**< Sdo request */
-                       )
-{
-    fsm->slave = slave;
-    fsm->request = request;
-    fsm->state = ec_fsm_coe_up_start;
+    if (request->dir == EC_DIR_OUTPUT)
+        fsm->state = ec_fsm_coe_down_start;
+    else
+        fsm->state = ec_fsm_coe_up_start;
 }
 
 /*****************************************************************************/
diff --git a/master/fsm_coe.h b/master/fsm_coe.h
index 758aa681..28976ea8 100644
--- a/master/fsm_coe.h
+++ b/master/fsm_coe.h
@@ -73,8 +73,7 @@ void ec_fsm_coe_init(ec_fsm_coe_t *, ec_datagram_t *);
 void ec_fsm_coe_clear(ec_fsm_coe_t *);
 
 void ec_fsm_coe_dictionary(ec_fsm_coe_t *, ec_slave_t *);
-void ec_fsm_coe_download(ec_fsm_coe_t *, ec_slave_t *, ec_sdo_request_t *);
-void ec_fsm_coe_upload(ec_fsm_coe_t *, ec_slave_t *, ec_sdo_request_t *);
+void ec_fsm_coe_transfer(ec_fsm_coe_t *, ec_slave_t *, ec_sdo_request_t *);
 
 int ec_fsm_coe_exec(ec_fsm_coe_t *);
 int ec_fsm_coe_success(ec_fsm_coe_t *);
diff --git a/master/fsm_coe_map.c b/master/fsm_coe_map.c
index b1e48b28..0bc352da 100644
--- a/master/fsm_coe_map.c
+++ b/master/fsm_coe_map.c
@@ -184,7 +184,7 @@ void ec_fsm_coe_map_action_next_dir(
         ec_sdo_request_address(&fsm->request, fsm->sync_sdo_index, 0);
         ecrt_sdo_request_read(&fsm->request);
         fsm->state = ec_fsm_coe_map_state_pdo_count;
-        ec_fsm_coe_upload(fsm->fsm_coe, fsm->slave, &fsm->request);
+        ec_fsm_coe_transfer(fsm->fsm_coe, fsm->slave, &fsm->request);
         ec_fsm_coe_exec(fsm->fsm_coe); // execute immediately
         return;
     }
@@ -240,7 +240,7 @@ void ec_fsm_coe_map_action_next_pdo(
                 fsm->sync_subindex);
         ecrt_sdo_request_read(&fsm->request);
         fsm->state = ec_fsm_coe_map_state_pdo;
-        ec_fsm_coe_upload(fsm->fsm_coe, fsm->slave, &fsm->request);
+        ec_fsm_coe_transfer(fsm->fsm_coe, fsm->slave, &fsm->request);
         ec_fsm_coe_exec(fsm->fsm_coe); // execute immediately
         return;
     }
@@ -297,7 +297,7 @@ void ec_fsm_coe_map_state_pdo(
     ec_sdo_request_address(&fsm->request, fsm->pdo->index, 0);
     ecrt_sdo_request_read(&fsm->request);
     fsm->state = ec_fsm_coe_map_state_pdo_entry_count;
-    ec_fsm_coe_upload(fsm->fsm_coe, fsm->slave, &fsm->request);
+    ec_fsm_coe_transfer(fsm->fsm_coe, fsm->slave, &fsm->request);
     ec_fsm_coe_exec(fsm->fsm_coe); // execute immediately
 }
 
@@ -344,7 +344,7 @@ void ec_fsm_coe_map_action_next_pdo_entry(
         ec_sdo_request_address(&fsm->request, fsm->pdo->index, fsm->pdo_subindex);
         ecrt_sdo_request_read(&fsm->request);
         fsm->state = ec_fsm_coe_map_state_pdo_entry;
-        ec_fsm_coe_upload(fsm->fsm_coe, fsm->slave, &fsm->request);
+        ec_fsm_coe_transfer(fsm->fsm_coe, fsm->slave, &fsm->request);
         ec_fsm_coe_exec(fsm->fsm_coe); // execute immediately
         return;
     }
diff --git a/master/fsm_master.c b/master/fsm_master.c
index 3a129997..67e17756 100644
--- a/master/fsm_master.c
+++ b/master/fsm_master.c
@@ -402,7 +402,7 @@ int ec_fsm_master_action_process_sdo(
                 fsm->sdo_request = req;
                 fsm->slave = slave;
                 fsm->state = ec_fsm_master_state_sdo_request;
-                ec_fsm_coe_upload(&fsm->fsm_coe, slave, req);
+                ec_fsm_coe_transfer(&fsm->fsm_coe, slave, req);
                 ec_fsm_coe_exec(&fsm->fsm_coe); // execute immediately
                 return 1;
             }
@@ -444,7 +444,7 @@ int ec_fsm_master_action_process_sdo(
         fsm->sdo_request = &request->req;
         fsm->slave = slave;
         fsm->state = ec_fsm_master_state_sdo_request;
-        ec_fsm_coe_upload(&fsm->fsm_coe, slave, &request->req);
+        ec_fsm_coe_transfer(&fsm->fsm_coe, slave, &request->req);
         ec_fsm_coe_exec(&fsm->fsm_coe); // execute immediately
         return 1;
     }
diff --git a/master/fsm_pdo_config.c b/master/fsm_pdo_config.c
index ac1cb810..02d3df02 100644
--- a/master/fsm_pdo_config.c
+++ b/master/fsm_pdo_config.c
@@ -220,7 +220,7 @@ void ec_fsm_pdo_config_next_pdo(
                 fsm->pdo->index);
 
     fsm->state = ec_fsm_pdo_config_state_zero_count;
-    ec_fsm_coe_download(fsm->fsm_coe, fsm->slave, &fsm->request);
+    ec_fsm_coe_transfer(fsm->fsm_coe, fsm->slave, &fsm->request);
     ec_fsm_coe_exec(fsm->fsm_coe); // execute immediately
 }
 
@@ -260,7 +260,7 @@ void ec_fsm_pdo_config_add_entry(
                 value, fsm->entry_count);
     
     fsm->state = ec_fsm_pdo_config_state_add_entry;
-    ec_fsm_coe_download(fsm->fsm_coe, fsm->slave, &fsm->request);
+    ec_fsm_coe_transfer(fsm->fsm_coe, fsm->slave, &fsm->request);
     ec_fsm_coe_exec(fsm->fsm_coe); // execute immediately
 }
 
@@ -326,7 +326,7 @@ void ec_fsm_pdo_config_state_add_entry(
                     fsm->entry_count);
         
         fsm->state = ec_fsm_pdo_config_state_entry_count;
-        ec_fsm_coe_download(fsm->fsm_coe, fsm->slave, &fsm->request);
+        ec_fsm_coe_transfer(fsm->fsm_coe, fsm->slave, &fsm->request);
         ec_fsm_coe_exec(fsm->fsm_coe); // execute immediately
         return;
     }
diff --git a/master/fsm_pdo_mapping.c b/master/fsm_pdo_mapping.c
index 758cefb7..571f23a8 100644
--- a/master/fsm_pdo_mapping.c
+++ b/master/fsm_pdo_mapping.c
@@ -210,7 +210,7 @@ void ec_fsm_pdo_mapping_next_dir(
             EC_DBG("Setting Pdo count to zero for SM%u.\n", fsm->sync->index);
 
         fsm->state = ec_fsm_pdo_mapping_state_zero_count;
-        ec_fsm_coe_download(fsm->fsm_coe, fsm->slave, &fsm->request);
+        ec_fsm_coe_transfer(fsm->fsm_coe, fsm->slave, &fsm->request);
         ec_fsm_coe_exec(fsm->fsm_coe); // execute immediately
         return;
     }
@@ -254,7 +254,7 @@ void ec_fsm_pdo_mapping_add_pdo(
                 fsm->pdo->index, fsm->pdo_count);
     
     fsm->state = ec_fsm_pdo_mapping_state_add_pdo;
-    ec_fsm_coe_download(fsm->fsm_coe, fsm->slave, &fsm->request);
+    ec_fsm_coe_transfer(fsm->fsm_coe, fsm->slave, &fsm->request);
     ec_fsm_coe_exec(fsm->fsm_coe); // execute immediately
 }
 
@@ -320,7 +320,7 @@ void ec_fsm_pdo_mapping_state_add_pdo(
                     fsm->pdo_count);
         
         fsm->state = ec_fsm_pdo_mapping_state_pdo_count;
-        ec_fsm_coe_download(fsm->fsm_coe, fsm->slave, &fsm->request);
+        ec_fsm_coe_transfer(fsm->fsm_coe, fsm->slave, &fsm->request);
         ec_fsm_coe_exec(fsm->fsm_coe); // execute immediately
         return;
     }
diff --git a/master/fsm_slave_config.c b/master/fsm_slave_config.c
index 0d664945..92a6766e 100644
--- a/master/fsm_slave_config.c
+++ b/master/fsm_slave_config.c
@@ -451,7 +451,7 @@ void ec_fsm_slave_config_enter_sdo_conf(ec_fsm_slave_config_t *fsm /**< slave st
     fsm->request = list_entry(fsm->slave->config->sdo_configs.next,
             ec_sdo_request_t, list);
     ecrt_sdo_request_write(fsm->request);
-    ec_fsm_coe_download(&fsm->fsm_coe, fsm->slave, fsm->request);
+    ec_fsm_coe_transfer(&fsm->fsm_coe, fsm->slave, fsm->request);
     ec_fsm_coe_exec(&fsm->fsm_coe); // execute immediately
 }
 
@@ -480,7 +480,7 @@ void ec_fsm_slave_config_state_sdo_conf(
         fsm->request = list_entry(fsm->request->list.next, ec_sdo_request_t,
                 list);
         ecrt_sdo_request_write(fsm->request);
-        ec_fsm_coe_download(&fsm->fsm_coe, fsm->slave, fsm->request);
+        ec_fsm_coe_transfer(&fsm->fsm_coe, fsm->slave, fsm->request);
         ec_fsm_coe_exec(&fsm->fsm_coe); // execute immediately
         return;
     }
diff --git a/master/sdo_request.c b/master/sdo_request.c
index 4e7ff2bd..cbbfdde7 100644
--- a/master/sdo_request.c
+++ b/master/sdo_request.c
@@ -57,6 +57,7 @@ void ec_sdo_request_init(
     req->data = NULL;
     req->mem_size = 0;
     req->data_size = 0;
+    req->dir = EC_DIR_OUTPUT;
     req->state = EC_REQUEST_COMPLETE;
 }
 
@@ -181,6 +182,7 @@ ec_sdo_request_error_t ecrt_sdo_request_error(const ec_sdo_request_t *req)
 
 void ecrt_sdo_request_read(ec_sdo_request_t *req)
 {
+    req->dir = EC_DIR_INPUT;
     req->state = EC_REQUEST_QUEUED;
 }
 
@@ -188,6 +190,7 @@ void ecrt_sdo_request_read(ec_sdo_request_t *req)
 
 void ecrt_sdo_request_write(ec_sdo_request_t *req)
 {
+    req->dir = EC_DIR_OUTPUT;
     req->state = EC_REQUEST_QUEUED;
 }
 
@@ -199,3 +202,5 @@ EXPORT_SYMBOL(ecrt_sdo_request_state);
 EXPORT_SYMBOL(ecrt_sdo_request_error);
 EXPORT_SYMBOL(ecrt_sdo_request_read);
 EXPORT_SYMBOL(ecrt_sdo_request_write);
+
+/*****************************************************************************/
diff --git a/master/sdo_request.h b/master/sdo_request.h
index 1d442ad6..a47733c5 100644
--- a/master/sdo_request.h
+++ b/master/sdo_request.h
@@ -58,6 +58,9 @@ struct ec_sdo_request {
     uint8_t *data; /**< Pointer to Sdo data. */
     size_t mem_size; /**< Size of Sdo data memory. */
     size_t data_size; /**< Size of Sdo data. */
+    ec_direction_t dir; /**< Direction. EC_DIR_OUTPUT means downloading to
+                          the slave, EC_DIR_INPUT means uploading from the
+                          slave. */
     ec_request_state_t state; /**< Sdo request state. */
 };
 
diff --git a/master/slave_config.c b/master/slave_config.c
index 985f6ce5..b688346e 100644
--- a/master/slave_config.c
+++ b/master/slave_config.c
@@ -709,6 +709,10 @@ ec_sdo_request_t *ecrt_slave_config_create_sdo_request(ec_slave_config_t *sc,
         kfree(req);
         return NULL;
     }
+
+    // prepare data for optional writing
+    memset(req->data, 0x00, size);
+    req->data_size = size;
     
     list_add_tail(&req->list, &sc->sdo_requests);
     return req;