I would like to display the current mute status on my Marantz receiver.
what am I doing wrong, the code needing to be sent is MU?\r

var s = CF.extender[A].serial[1];
s.bitrate = 9600;
s.databits = 8;
s.parity = 0;
s.stopbits = 1;
var line = s.match('MU?\r','\r',1000);
CF.widget("Mute_Status").label = line;