diff --git a/extensions/openpower-pels/callout.cpp b/extensions/openpower-pels/callout.cpp
new file mode 100644
index 0000000..53fe85d
--- /dev/null
+++ b/extensions/openpower-pels/callout.cpp
@@ -0,0 +1,102 @@
+#include "callout.hpp"
+
+#include <phosphor-logging/log.hpp>
+
+namespace openpower
+{
+namespace pels
+{
+namespace src
+{
+
+using namespace phosphor::logging;
+
+Callout::Callout(Stream& pel)
+{
+    pel >> _size >> _flags >> _priority >> _locationCodeSize;
+
+    if (_locationCodeSize)
+    {
+        _locationCode.resize(_locationCodeSize);
+        pel >> _locationCode;
+    }
+
+    size_t currentSize = 4 + _locationCodeSize;
+
+    // Read in the substructures until the end of this structure.
+    // Any stream overflows will throw an exception up to the SRC constructor
+    while (_size > currentSize)
+    {
+        // Peek the type
+        uint16_t type = 0;
+        pel >> type;
+        pel.offset(pel.offset() - 2);
+
+        switch (type)
+        {
+            case FRUIdentity::substructureType:
+            {
+                _fruIdentity = std::make_unique<FRUIdentity>(pel);
+                currentSize += _fruIdentity->flattenedSize();
+                break;
+            }
+            case PCEIdentity::substructureType:
+            {
+                _pceIdentity = std::make_unique<PCEIdentity>(pel);
+                currentSize += _pceIdentity->flattenedSize();
+                break;
+            }
+            case MRU::substructureType:
+            {
+                _mru = std::make_unique<MRU>(pel);
+                currentSize += _mru->flattenedSize();
+                break;
+            }
+            default:
+                log<level::ERR>("Invalid Callout subsection type",
+                                entry("CALLOUT_TYPE=0x%X", type));
+                throw std::runtime_error("Invalid Callout subsection type");
+                break;
+        }
+    }
+}
+
+size_t Callout::flattenedSize()
+{
+    size_t size = sizeof(_size) + sizeof(_flags) + sizeof(_priority) +
+                  sizeof(_locationCodeSize) + _locationCodeSize;
+
+    size += _fruIdentity ? _fruIdentity->flattenedSize() : 0;
+    size += _pceIdentity ? _pceIdentity->flattenedSize() : 0;
+    size += _mru ? _mru->flattenedSize() : 0;
+
+    return size;
+}
+
+void Callout::flatten(Stream& pel)
+{
+    pel << _size << _flags << _priority << _locationCodeSize;
+
+    if (_locationCodeSize)
+    {
+        pel << _locationCode;
+    }
+
+    if (_fruIdentity)
+    {
+        _fruIdentity->flatten(pel);
+    }
+
+    if (_pceIdentity)
+    {
+        _pceIdentity->flatten(pel);
+    }
+    if (_mru)
+    {
+        _mru->flatten(pel);
+    }
+}
+
+} // namespace src
+} // namespace pels
+} // namespace openpower