diff --git a/grc/misc_utils/gsm_trx_burst_if.xml b/grc/misc_utils/gsm_trx_burst_if.xml
index d3dab5c..252cf6a 100644
--- a/grc/misc_utils/gsm_trx_burst_if.xml
+++ b/grc/misc_utils/gsm_trx_burst_if.xml
@@ -32,32 +32,15 @@
   </source>
 
   <doc>
-      OsmoTRX like UDP interface for external applications.
+      OsmoTRX like UDP burst interface for external applications.
 
-      There are three UDP sockets: CLCK, CTRL and DATA.
-      Give a base port B (5700 by default), the SCH clock
-      interface is at port P=B. The TRX-side control interface
-      is on port P=B+100+1 and the data interface is on an odd
-      numbered port P=B+100+2.
+      There are two UDP connections, where each message carries
+      one radio burst with header. Give a base port B (5700 by default).
+      One connection at port P=B+100+2 is used for sending received bursts
+      to an external application. Another one at port P=B+2 is used to
+      obtain to be transmitted bursts.
 
-      Indications on the SCH Clock Interface (CLCK)
-      The SCH clock interface is output only (from the radio).
-      CLOCK gives the current value of the BTS clock to
-      be used by external applications. The indications are
-      sent whenever a transmission packet arrives that is too
-      late or too early.
-
-      Commands on Control Interface (CTRL)
-      The control interface uses a command-response protocol.
-      Commands are NULL-terminated ASCII strings. Each command
-      has a corresponding response. This interface isn't handled
-      by this particular block, and should be implemented outside.
-
-      Messages on the Data Interface
-      Messages on the data interface carry one radio burst per
-      UDP message.
-
-      Received Data Burst:
+      Received burst format:
       1 byte timeslot index
       4 bytes GSM frame number, big endian
       1 byte RSSI in -dBm
@@ -66,7 +49,7 @@
       148 bytes soft symbol estimates, 0 -&gt; definite "0",
           255 -&gt; definite "1"
 
-      Transmit Data Burst:
+      To be transmitted burst format:
       1 byte timeslot index
       4 bytes GSM frame number, big endian
       1 byte transmit level wrt ARFCN max, -dB (attenuation)