Automating XML communication over serial port using Perl -

i trying automate xml communication modem on serial port, modem accepts xml request , provides xml response events, response format .... , events format ... have written perl code unable capture complete response. need solution , waiting desperately it...

here perl code

#!/bin/perl #to open com1 port use io::handle; #below initialization request $initreq = "<request timestamp=\"1331734792\"><get resource=\"mod.security.session\"/></request>"; $nak = "<nak/>"; $ack = "<ack/>";  #logic starts here  $com_port = "/dev/ttys0"; print "trying open $com_port\n"; system ("mode /dev/ttys0 baud=115200 stop=1 data=8 parity=n rts=off dtr=off"); open dev,"+>$com_port" or die "failed open com port\n"; print "port opened \n"; $ofh = select(dev);  $| = 0;  $/='>';  select($ofh); print "sending session initialization command\n"; print dev "$initreq"; $out = <dev>; print "initialization response: $out \n" ;     #below line sends login request print dev "<request session=\"1\" timestamp=\"9876543210\"><set resource=\"mod\"><login>true</login><pin>abcd</pin></set></request>"; $out = <dev>; print "login response: $out";     #below gets responses print dev "<request session=\"1\" timestamp=\"07012013174726006\"><get resource=\"mod.sensors.{1}\"/></request>"; $out = <dev>; print "get sensor n details response: $out \n";     #the below logout request print dev "<request session=\"1\" timestamp=\"9876543211\"><set resource=\"nmp\"><login>false</login></set></request>"; $out = <dev>; print "logout response: $out \n";