Handle extended packet lengths.

POCSAGTX.cpp

@@ -1,5 +1,5 @@
 /*
- *   Copyright (C) 2009-2018 by Jonathan Naylor G4KLX
+ *   Copyright (C) 2009-2018,2020 by Jonathan Naylor G4KLX
  *
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -95,7 +95,7 @@ bool CPOCSAGTX::busy()
     return false;
 }
 
-uint8_t CPOCSAGTX::writeData(const uint8_t* data, uint8_t length)
+uint8_t CPOCSAGTX::writeData(const uint8_t* data, uint16_t length)
 {
   if (length != POCSAG_FRAME_LENGTH_BYTES)
     return 4U;