RS232　interfaces　are　widely　used　in　data　transmission,　such　as　wireless　meter　reading,　digital　image　transmission,　industrial　data　collection,　cell　paging,　fire-proof　system,　radio　frequency　identification　card,　local　alarm　system,　and　so　on.　Since　the　longest　distance　of　cable　transmission　is　only　15　meters,　so　it　is　important　to　develop　a　kind　of　RS232　interface　used　for　wireless　transmission.　ZigBee　is　a　new　and　popular　protocol　for　wireless　communication　because　of　its　low　power　assumption,　large　network　capacity　and　the　ability　to　organize　a　network　automatically.　The　scheme　of　converting　RS232　signal　into　wireless　signal　is　introduced.　MAX232　is　used　to　connect　RS232　interface　with　ZigBee　module,　and　CC2430　with　internal　C51　is　used　to　be　programmed　for　wireless　communication.　©　2010　IEEE.