diff --git a/src/host/modem/Modem.h b/src/host/modem/Modem.h
index 866cd9d1..4bd97bcc 100644
--- a/src/host/modem/Modem.h
+++ b/src/host/modem/Modem.h
@@ -493,7 +493,7 @@ namespace modem
          * @brief Helper to test if the P25 ring buffer has free space.
          * @returns bool True, if the P25 ring buffer has free space, otherwise false.
          */
-        bool hasP25Space(uint32_t length) const;
+        virtual bool hasP25Space(uint32_t length) const;
         /**
          * @brief Helper to test if the NXDN ring buffer has free space.
          * @returns bool True, if the NXDN ring buffer has free space, otherwise false.
diff --git a/src/host/modem/ModemV24.cpp b/src/host/modem/ModemV24.cpp
index 4a6cbc39..e681de90 100644
--- a/src/host/modem/ModemV24.cpp
+++ b/src/host/modem/ModemV24.cpp
@@ -389,6 +389,13 @@ void ModemV24::close()
     }
 }
 
+/* Helper to test if the P25 ring buffer has free space. */
+
+bool ModemV24::hasP25Space(uint32_t length) const
+{
+    return Modem::hasP25Space(length);
+}
+
 /* Writes raw data to the air interface modem. */
 
 int ModemV24::write(const uint8_t* data, uint32_t length)
diff --git a/src/host/modem/ModemV24.h b/src/host/modem/ModemV24.h
index 4477f6f0..71a126ed 100644
--- a/src/host/modem/ModemV24.h
+++ b/src/host/modem/ModemV24.h
@@ -278,6 +278,12 @@ namespace modem
          */
         void close() override;
 
+        /**
+         * @brief Helper to test if the P25 ring buffer has free space.
+         * @returns bool True, if the P25 ring buffer has free space, otherwise false.
+         */
+        bool hasP25Space(uint32_t length) const override;
+
         /**
          * @brief Writes raw data to the air interface modem.
          * @param data Data to write to modem.