diff --git a/applications/utilities/preProcessing/createExternalCoupledPatchGeometry/createExternalCoupledPatchGeometry.C b/applications/utilities/preProcessing/createExternalCoupledPatchGeometry/createExternalCoupledPatchGeometry.C
index e2f8a244af..dc0348da1a 100644
--- a/applications/utilities/preProcessing/createExternalCoupledPatchGeometry/createExternalCoupledPatchGeometry.C
+++ b/applications/utilities/preProcessing/createExternalCoupledPatchGeometry/createExternalCoupledPatchGeometry.C
@@ -28,6 +28,19 @@ Description
     Application to generate the patch geometry (points and faces) for use
     with the externalCoupled boundary condition.
 
+    Usage:
+
+        createExternalCoupledPatchGeometry <fieldName>
+
+    On execution, the field <fieldName> is read, and its boundary conditions
+    interrogated for the presence of an \c externalCoupled type.  If found,
+    the patch geometry (points and faces) for the coupled patches are output
+    to the communications folder.
+
+Note:
+    The addressing is patch-local, i.e. point indices for each patch point
+    used for face addressing starts at index 0.
+
 SeeAlso
     externalCoupledMixedFvPatchField
 
diff --git a/src/finiteVolume/fields/fvPatchFields/derived/externalCoupledMixed/externalCoupledMixedFvPatchField.H b/src/finiteVolume/fields/fvPatchFields/derived/externalCoupledMixed/externalCoupledMixedFvPatchField.H
index ef8ef2bc11..cfe08cd78e 100644
--- a/src/finiteVolume/fields/fvPatchFields/derived/externalCoupledMixed/externalCoupledMixedFvPatchField.H
+++ b/src/finiteVolume/fields/fvPatchFields/derived/externalCoupledMixed/externalCoupledMixedFvPatchField.H
@@ -32,34 +32,46 @@ Description
     Values are transferred as plain text files, where OperFOAM data is written
     as:
 
-        <value1> <surfaceNormalGradient1>
-        <value2> <surfaceNormalGradient2>
-        <value3> <surfaceNormalGradient3>
+        # Patch: <patch name>
+        <magSf1> <value1> <surfaceNormalGradient1>
+        <magSf2> <value2> <surfaceNormalGradient2>
+        <magSf3> <value3> <surfaceNormalGradient3>
         ...
-        <valueN> <surfaceNormalGradientN>
+        <magSfN> <valueN> <surfaceNormalGradientN>
 
     and received as the constituent pieces of the `mixed' condition, i.e.
 
+        # Patch: <patch name>
         <value1> <gradient1> <valueFracion1>
         <value2> <gradient2> <valueFracion2>
         <value3> <gradient3> <valueFracion3>
         ...
         <valueN> <gradientN> <valueFracionN>
 
-    At start-up, the boundary creates a lock file, e.g.
+    Data is either sent/received as one file per patch, or as a single file
+    for all patches, based on the \c collate flag.  In the former case, the
+    folder used for communications is:
 
-        $FOAM_CASE/comms/patchName/OpenFOAM.lock
+        $FOAM_CASE/<commsDir>/patchName
+
+    and when using the \c collate option:
+
+        $FOAM_CASE/<commsDir>
+
+    At start-up, the boundary creates a lock file, i.e..
+
+        OpenFOAM.lock
 
     ... to signal the external source to wait.  During the boundary condition
     update, boundary values are written to file, e.g.
 
-        $FOAM_CASE/comms/patchName/data.out
+        <fileName>.out
 
     The lock file is then removed, instructing the external source to take
     control of the program execution.  When ready, the external program
     should create the return values, e.g. to file
 
-        $FOAM_CASE/comms/patchName/data.in
+        <fileName>.in
 
     ... and then re-instate the lock file.  The boundary condition will then
     read the return values, and pass program execution back to OpenFOAM.
diff --git a/src/turbulenceModels/compressible/turbulenceModel/derivedFvPatchFields/externalCoupledTemperatureMixed/externalCoupledTemperatureMixedFvPatchScalarField.H b/src/turbulenceModels/compressible/turbulenceModel/derivedFvPatchFields/externalCoupledTemperatureMixed/externalCoupledTemperatureMixedFvPatchScalarField.H
index 7be0649999..906f878ed8 100644
--- a/src/turbulenceModels/compressible/turbulenceModel/derivedFvPatchFields/externalCoupledTemperatureMixed/externalCoupledTemperatureMixedFvPatchScalarField.H
+++ b/src/turbulenceModels/compressible/turbulenceModel/derivedFvPatchFields/externalCoupledTemperatureMixed/externalCoupledTemperatureMixedFvPatchScalarField.H
@@ -32,34 +32,46 @@ Description
     application.  Values are transferred as plain text files, where OperFOAM
     data is written as:
 
-        <value1> <surfaceNormalGradient1>
-        <value2> <surfaceNormalGradient2>
-        <value3> <surfaceNormalGradient3>
+        # Patch: <patch name>
+        <magSf1> <value1> <qDot1> <htc1>
+        <magSf2> <value2> <qDot2> <htc2>
+        <magSf3> <value3> <qDot3> <htc2>
         ...
-        <valueN> <surfaceNormalGradientN>
+        <magSfN> <valueN> <qDotN> <htcN>
 
     and received as the constituent pieces of the `mixed' condition, i.e.
 
+        # Patch: <patch name>
         <value1> <gradient1> <valueFracion1>
         <value2> <gradient2> <valueFracion2>
         <value3> <gradient3> <valueFracion3>
         ...
         <valueN> <gradientN> <valueFracionN>
 
-    At start-up, the boundary creates a lock file, e.g.
+    Data is either sent/received as one file per patch, or as a single file
+    for all patches, based on the \c collate flag.  In the former case, the
+    folder used for communications is:
 
-        $FOAM_CASE/comms/patchName/OpenFOAM.lock
+        $FOAM_CASE/<commsDir>/patchName
+
+    and when using the \c collate option:
+
+        $FOAM_CASE/<commsDir>
+
+    At start-up, the boundary creates a lock file, i.e..
+
+        OpenFOAM.lock
 
     ... to signal the external source to wait.  During the boundary condition
     update, boundary values are written to file, e.g.
 
-        $FOAM_CASE/comms/patchName/data.out
+        <fileName>.out
 
     The lock file is then removed, instructing the external source to take
     control of the program execution.  When ready, the external program
     should create the return values, e.g. to file
 
-        $FOAM_CASE/comms/patchName/data.in
+        <fileName>.in
 
     ... and then re-instate the lock file.  The boundary condition will then
     read the return values, and pass program execution back to OpenFOAM.