diff --git a/System/Hardware/Serialport/Posix.hs b/System/Hardware/Serialport/Posix.hs
--- a/System/Hardware/Serialport/Posix.hs
+++ b/System/Hardware/Serialport/Posix.hs
@@ -4,6 +4,7 @@
 import System.IO
 import System.Posix.Terminal
 import System.Posix.IO
+import Data.Word
 
 
 data StopBits = One | Two
@@ -20,7 +21,7 @@
 -}
 hOpenSerial :: String      -- ^ The filename of the serial port, such as @/dev/ttyS0@ or @/dev/ttyUSB0@
            -> BaudRate     
-           -> Int          -- ^ The number of bits per word, typically 8
+           -> Word8          -- ^ The number of bits per word, typically 8
            -> StopBits     -- ^ Almost always @One@ unless you're talking to a printer
            -> Parity       -- ^ Error checking       
            -> FlowControl
@@ -35,7 +36,7 @@
 
 openSerial :: String       -- ^ The filename of the serial port, such as @/dev/ttyS0@
            -> BaudRate     
-           -> Int          -- ^ The number of bits per word, typically 8
+           -> Word8          -- ^ The number of bits per word, typically 8
            -> StopBits     -- ^ Almost always @One@ unless you're talking to a printer
            -> Parity       
            -> FlowControl
@@ -48,7 +49,7 @@
 
 setSerial :: String       
            -> BaudRate     
-           -> Int          
+           -> Word8          
            -> StopBits     
            -> Parity       
            -> FlowControl
@@ -87,11 +88,11 @@
 withStopBits termOpts Two = termOpts `withMode` TwoStopBits
 
 
-configureSettings :: TerminalAttributes -> BaudRate -> Int -> StopBits -> Parity -> FlowControl -> TerminalAttributes
+configureSettings :: TerminalAttributes -> BaudRate -> Word8 -> StopBits -> Parity -> FlowControl -> TerminalAttributes
 configureSettings termOpts baud bPerB stopBits parity flow =
     termOpts `withInputSpeed` baud
                  `withOutputSpeed` baud
-                 `withBits` bPerB
+                 `withBits` (fromIntegral bPerB :: Int)
                  `withStopBits` stopBits
                  `withParity` parity
                  `withFlowControl` flow
diff --git a/System/Hardware/Serialport/Windows.hs b/System/Hardware/Serialport/Windows.hs
--- a/System/Hardware/Serialport/Windows.hs
+++ b/System/Hardware/Serialport/Windows.hs
@@ -4,6 +4,7 @@
 import System.Win32.File
 import System.Win32.Types
 import Data.Bits
+import Data.Word
 import Control.Concurrent
 import System.Win32.Comm
 import Foreign.Marshal.Alloc
@@ -18,7 +19,7 @@
 
 openSerial :: String      -- ^ The filename of the serial port, such as @COM5@ or @//./CNCA0@
            -> BaudRate
-           -> Int
+           -> Word8
            -> StopBits
            -> Parity
            -> FlowControl
@@ -38,7 +39,7 @@
 
 setSerial :: HANDLE
            -> BaudRate     
-           -> Int          
+           -> Word8          
            -> StopBits     
            -> Parity       
            -> FlowControl
diff --git a/System/Win32/Comm.hsc b/System/Win32/Comm.hsc
--- a/System/Win32/Comm.hsc
+++ b/System/Win32/Comm.hsc
@@ -77,7 +77,7 @@
       parity :: Parity,
       stopBits :: StopBits,
       flowControl :: FlowControl,
-      byteSize :: Int
+      byteSize :: Word8
      } deriving Show
 
 
diff --git a/serialport.cabal b/serialport.cabal
--- a/serialport.cabal
+++ b/serialport.cabal
@@ -1,5 +1,5 @@
 Name:           serialport
-Version:        0.1.0
+Version:        0.1.0.1
 Cabal-Version:  >= 1.2
 Build-Type:     Simple
 license:        BSD3