diff --git a/master/cdev.c b/master/cdev.c
index a667f469..bef261c1 100644
--- a/master/cdev.c
+++ b/master/cdev.c
@@ -273,7 +273,7 @@ int ec_cdev_ioctl_slave(
     data.dc_supported = slave->base_dc_supported;
     data.dc_range = slave->base_dc_range;
     data.has_dc_system_time = slave->has_dc_system_time;
-    data.transition_delay = slave->transition_delay;
+    data.transmission_delay = slave->transmission_delay;
     data.al_state = slave->current_state;
     data.error_flag = slave->error_flag;
 
diff --git a/master/ioctl.h b/master/ioctl.h
index 05f355d3..23b891dd 100644
--- a/master/ioctl.h
+++ b/master/ioctl.h
@@ -176,7 +176,7 @@ typedef struct {
     uint8_t dc_supported;
     ec_slave_dc_range_t dc_range;
     uint8_t has_dc_system_time;
-    uint32_t transition_delay;
+    uint32_t transmission_delay;
     uint8_t al_state;
     uint8_t error_flag;
     uint8_t sync_count;
diff --git a/master/master.c b/master/master.c
index 5a685613..b7a7d0a9 100644
--- a/master/master.c
+++ b/master/master.c
@@ -1431,9 +1431,9 @@ void ec_master_calc_topology(
 
 /*****************************************************************************/
 
-/** Calculates the bus transition delays.
+/** Calculates the bus transmission delays.
  */
-void ec_master_calc_transition_delays(
+void ec_master_calc_transmission_delays(
         ec_master_t *master /**< EtherCAT master. */
 		)
 {
@@ -1447,7 +1447,7 @@ void ec_master_calc_transition_delays(
 
     if (master->dc_ref_clock) {
         uint32_t delay = 0;
-        ec_slave_calc_transition_delays_rec(master->dc_ref_clock, &delay);
+        ec_slave_calc_transmission_delays_rec(master->dc_ref_clock, &delay);
     }
 }
 
@@ -1465,7 +1465,7 @@ void ec_master_calc_dc(
     // calculate bus topology
     ec_master_calc_topology(master);
 
-    ec_master_calc_transition_delays(master);
+    ec_master_calc_transmission_delays(master);
 }
 
 /******************************************************************************
diff --git a/master/slave.c b/master/slave.c
index 6963c3f2..e19a2f1c 100644
--- a/master/slave.c
+++ b/master/slave.c
@@ -106,7 +106,7 @@ void ec_slave_init(
     slave->base_dc_supported = 0;
     slave->base_dc_range = EC_DC_32;
     slave->has_dc_system_time = 0;
-    slave->transition_delay = 0U;
+    slave->transmission_delay = 0U;
 
     slave->sii_words = NULL;
     slave->sii_nwords = 0;
@@ -792,7 +792,7 @@ ec_slave_t *ec_slave_find_next_dc_slave(
 
 /*****************************************************************************/
 
-/** Calculates the port transition delays.
+/** Calculates the port transmission delays.
  */
 void ec_slave_calc_port_delays(
         ec_slave_t *slave /**< EtherCAT slave. */
@@ -829,9 +829,9 @@ void ec_slave_calc_port_delays(
 
 /*****************************************************************************/
 
-/** Calculates the bus topology; recursion function.
+/** Recursively calculates transmission delays.
  */
-void ec_slave_calc_transition_delays_rec(
+void ec_slave_calc_transmission_delays_rec(
         ec_slave_t *slave, /**< Current slave. */
         uint32_t *delay /**< Sum of delays. */
 		)
@@ -843,7 +843,7 @@ void ec_slave_calc_transition_delays_rec(
     EC_DBG("%u: %u\n", slave->ring_position, *delay);
 #endif
 
-    slave->transition_delay = *delay;
+    slave->transmission_delay = *delay;
 
     for (i = 1; i < EC_MAX_PORTS; i++) {
         ec_slave_port_t *port = &slave->ports[i];
@@ -858,7 +858,7 @@ void ec_slave_calc_transition_delays_rec(
 #if 0
         EC_DBG("%u:%u %u\n", slave->ring_position, i, *delay);
 #endif
-        ec_slave_calc_transition_delays_rec(next_dc, delay);
+        ec_slave_calc_transmission_delays_rec(next_dc, delay);
     }
 
     *delay = *delay + slave->ports[0].delay_to_next_dc;
diff --git a/master/slave.h b/master/slave.h
index 2996f41d..aa7fb707 100644
--- a/master/slave.h
+++ b/master/slave.h
@@ -141,8 +141,8 @@ struct ec_slave
     uint8_t has_dc_system_time; /**< The slave supports the DC system time
                                   register. Otherwise it can only be used for
                                   delay measurement. */
-    uint32_t transition_delay; /**< DC transition delay (from reference
-                                 clock). */
+    uint32_t transmission_delay; /**< DC system time transmission delay
+                                   (offset from reference clock). */
 
     // SII
     uint16_t *sii_words; /**< Complete SII image. */
@@ -187,7 +187,7 @@ const ec_pdo_t *ec_slave_find_pdo(const ec_slave_t *, uint16_t);
 void ec_slave_attach_pdo_names(ec_slave_t *);
 
 void ec_slave_calc_port_delays(ec_slave_t *);
-void ec_slave_calc_transition_delays_rec(ec_slave_t *, uint32_t *);
+void ec_slave_calc_transmission_delays_rec(ec_slave_t *, uint32_t *);
 
 /*****************************************************************************/
 
diff --git a/tool/CommandGraph.cpp b/tool/CommandGraph.cpp
index 171adc9f..a625349f 100644
--- a/tool/CommandGraph.cpp
+++ b/tool/CommandGraph.cpp
@@ -139,7 +139,7 @@ void CommandGraph::execute(MasterDevice &m, const StringVector &args)
             } else {
                 cout << "Delay meas.";
             }
-            cout << "\\nDelay: " << si->transition_delay << " ns";
+            cout << "\\nDelay: " << si->transmission_delay << " ns";
         }
         cout << "\"]" << endl;
 
diff --git a/tool/CommandSlaves.cpp b/tool/CommandSlaves.cpp
index ebdfd171..28f0af6c 100644
--- a/tool/CommandSlaves.cpp
+++ b/tool/CommandSlaves.cpp
@@ -262,8 +262,8 @@ void CommandSlaves::showSlaves(
             } else {
                 cout << "yes, delay measurement only" << endl;
             }
-            cout << "  DC transition delay: "
-                << si->transition_delay << " ns" << endl;
+            cout << "  DC system time transmission delay: "
+                << si->transmission_delay << " ns" << endl;
         } else {
             cout << "no" << endl;
         }