diff -ur v1/sock_ut.py v2/sock_ut.py
--- v1/sock_ut.py	2021-06-09 16:10:05.000000000 +0900
+++ v2/sock_ut.py	2021-06-10 21:09:48.000000000 +0900
@@ -17,26 +17,32 @@
 		return None
 	return cs
 
-def send_str( sc, s ):
-	bt = s.encode( 'utf-8' )
+def send_bt( sc, bt ):
 	try:
 		sc.sendall( bt )
 	except:
 		return False
 	return True
 
-def recv_str( sc ):
+def recv_bt( sc ):
 	bufmax = 16 * 1024
 	bt = sc.recv( bufmax )
-	s = bt.decode( 'utf-8' )
-	return s
+	return bt
+
+def send_str( sc, s ):
+	bt = s.encode( 'utf-8' )
+	return send_bt( sc, bt )
+
+def recv_str( sc ):
+	bt = recv_bt( sc )
+	return bt.decode( 'utf-8' )
 
 def pipe_loop( sc_from, sc_to ):
 	while True:
-		s = recv_str( sc_from )
-		if not s:
+		bt = recv_bt( sc_from )
+		if not bt:
 			break
-		if not send_str( sc_to, s ):
+		if not send_bt( sc_to, bt ):
 			break
 
 # srv=name