diff --git a/README.md b/README.md
index 9356f25..c8df125 100644
--- a/README.md
+++ b/README.md
@@ -27,9 +27,9 @@ Below some really basic usage how I am ca using it:
         if let Ok(Some((ip, port, len))) = (w5500, socket).receive(&mut buffer[..]) {
             let (request_buffer, response_buffer) = buffer.split_mut_at(len);
 
-            //...
+            // ... fill the response_buffer with some data ...
 
-            (w5500, socket).blocking_send(ip, port, 1234, response_buffer[..response_len]).unwrap();
+            (w5500, socket).blocking_send(ip, port, response_buffer[..response_len]).unwrap();
         }
     }
 ```
diff --git a/src/lib.rs b/src/lib.rs
index eacab2c..b51ef3f 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -351,7 +351,6 @@ pub trait Udp<E> {
         &mut self,
         host: &IpAddress,
         host_port: u16,
-        local_port: u16,
         data: &[u8],
     ) -> Result<(), E>;
 }
@@ -412,12 +411,12 @@ impl<E> Udp<E> for (&mut ActiveW5500<'_, '_, '_, E>, &UdpSocket) {
         &mut self,
         host: &IpAddress,
         host_port: u16,
-        local_port: u16,
         data: &[u8],
     ) -> Result<(), E> {
         let (w5500, UdpSocket(socket)) = self;
 
         {
+            let local_port = w5500.read_u16(socket.at(SocketRegister::LocalPort))?;
             let local_port = u16_to_be_bytes(local_port);
             let host_port = u16_to_be_bytes(host_port);