How to send a command to RFlink connected to USB in / dev / ttyUSB0

I have a text box linked to the serial port that perfectly receives the information from the RFlink
But I can not send orders on this one.

My sitemap:{
     sitemap rf_test  label= "RfLink Test"{
         Text item=RFLinkRaw // ["%s"]
My items
String RFLinkRaw	"RFLink raw data [%s]" <text> { serial="/dev/ttyUSB0@57600" }
Switch Test_RFlinj    "Send Command"        
My rules

rule "RFLink IN"
              Item RFLinkRaw received update
           //treatment values received

rule "RFLink OUT"
         Item Test_RFlink received command ON
         val reponse = RFLinkRaw.sendCommand("10;Newkaku;02128800;1;ON")  

When I send the command I receive this error:
16:01:43.799 [ERROR] [untime.internal.engine.RuleEngineImpl] - Rule ‘RFLink IN’: 5

I do not have to have everything understood to send information on / dev / ttyUSB0 …
Please Help me

I have the exact same issue. Someone propose me to use RFLink Bindding (and I will give it a try in the next few days) but I would understand how to send data through serial binding too. If someone could give some hint it will be very appreciated.