diff --git a/ptb/shutter_protocol.py b/ptb/shutter_protocol.py
index 8023b56..4fcb9ad 100644
--- a/ptb/shutter_protocol.py
+++ b/ptb/shutter_protocol.py
@@ -12,16 +12,15 @@ def do(self, cmd):
         logger.debug("do %s", cmd)
         self._writeline(cmd)
 
-    async def ask(self, cmd):
+    async def ask(self, cmd, n=None):
         self.do(cmd)
-        ret = await self._readline()
+        if n is None:
+            ret = await self._readline()
+        else:
+            ret = await self._read(n)
         logger.debug("ret %s", ret)
         return ret
 
-    async def read(self, n):
-        ret = await self._read(n)
-        return ret.decode()
-
     async def version(self):
         """Return the hardware/firmware version.
 
@@ -36,8 +35,7 @@ async def status(self):
         Returns:
             list(float): Temperatures on all channels
         """
-        ret = (await self.ask(b"e")).strip()
-        assert len(ret) == 3
+        ret = (await self.ask(b"e", 3)).strip()
         return tuple(bool(int(_)) for _ in ret)
 
     def clear(self):
diff --git a/ptb/shutter_tcp.py b/ptb/shutter_tcp.py
index ca9d75e..be5e287 100644
--- a/ptb/shutter_tcp.py
+++ b/ptb/shutter_tcp.py
@@ -4,7 +4,7 @@
 
 
 class ShutterTCP(ShutterProtocol):
-    eol_write = b"\r"
+    eol_write = b"\r\n"
     eol_read = b"\r"
 
     def __init__(self, reader, writer):
@@ -29,8 +29,9 @@ def _writeline(self, cmd):
         self._writer.write(cmd + self.eol_write)
 
     async def _readline(self):
-        r = await self._reader.readline()
-        assert r.endswith(self.eol_read)
+        r = b""
+        while not r.endswith(self.eol_read):
+            r += await self._reader.read(1)
         return r[:-len(self.eol_read)]
 
     async def _read(self, n):
diff --git a/test_shutter.py b/test_shutter.py
index 83c87b2..87adcc8 100644
--- a/test_shutter.py
+++ b/test_shutter.py
@@ -8,16 +8,17 @@
 
 async def test(dev):
     print(dev)
-    print(await dev.version())
     print(await dev.status())
-    print(await dev.passthrough(1, b"W"))
+    print(await dev.version())
+    for i in b"TWXYZ":
+        print(i, await dev.passthrough(1, i))
 
 def main():
-    logging.basicConfig(level=logging.INFO)
+    logging.basicConfig(level=logging.DEBUG)
     loop = asyncio.get_event_loop()
     loop.set_debug(False)
     async def run():
-        with await Synth.connect("buemi") as dev:
+        with await Shutter.connect("buemi") as dev:
             await test(dev)
     loop.run_until_complete(run())