diff --git a/linux/devices/SusPolling.cpp b/linux/devices/SusPolling.cpp
index 1b7d3605..e5d330a3 100644
--- a/linux/devices/SusPolling.cpp
+++ b/linux/devices/SusPolling.cpp
@@ -18,7 +18,21 @@ ReturnValue_t SusPolling::performOperation(uint8_t operationCode) {
     state = InternalState::IDLE;
     ipcLock->unlockMutex();
     semaphore->acquire();
-    // TODO: Perform SUS polling here.
+    for(auto& susDev: susDevs) {
+      acs::SimpleSensorMode mode;
+      bool doPerformStartup = false;
+      {
+        MutexGuard mg(ipcLock);
+        mode = susDev.mode;
+        doPerformStartup = susDev.performStartup;
+      }
+      if (mode == acs::SimpleSensorMode::NORMAL) {
+        if(doPerformStartup) {
+          // Startup handling.
+        }
+        // Regular sensor polling.
+      }
+    }
   }
   return OK;
 }
@@ -51,7 +65,14 @@ ReturnValue_t SusPolling::sendMessage(CookieIF* cookie, const uint8_t* sendData,
     return FAILED;
   }
   const auto* susReq = reinterpret_cast<const acs::SusRequest*>(sendData);
+  MutexGuard mg(ipcLock);
   if (susDevs[susIdx].mode != susReq->mode) {
+    if(susReq->mode == acs::SimpleSensorMode::NORMAL) {
+     susDevs[susIdx].performStartup = true;
+    } else {
+      susDevs[susIdx].ownReply.dataWasSet = false;
+    }
+    susDevs[susIdx].mode = susReq->mode;
   }
   return OK;
 }
@@ -61,6 +82,18 @@ ReturnValue_t SusPolling::getSendSuccess(CookieIF* cookie) { return OK; }
 ReturnValue_t SusPolling::requestReceiveMessage(CookieIF* cookie, size_t requestLen) { return OK; }
 
 ReturnValue_t SusPolling::readReceivedMessage(CookieIF* cookie, uint8_t** buffer, size_t* size) {
+  auto* spiCookie = dynamic_cast<SpiCookie*>(cookie);
+  if (spiCookie == nullptr) {
+    return FAILED;
+  }
+  int susIdx = addressToIndex(spiCookie->getSpiAddress());
+  if (susIdx < 0) {
+    return FAILED;
+  }
+  MutexGuard mg(ipcLock);
+  std::memcpy(&susDevs[susIdx].readerReply, &susDevs[susIdx].ownReply, sizeof(acs::SusReply));
+  *buffer = reinterpret_cast<uint8_t*>(&susDevs[susIdx].readerReply);
+  *size = sizeof(acs::SusReply);
   return OK;
 }