«<Impact>» reads until a newline is received. If the first message is "blank", it's because there was nothing before the first newline.

Update: Well, that's not right. (Tired today.) But then, neither is the question. What is this code you posted, and why isn't it the code that exhibits the problem? You only have one read, yet you talk of the wrong read getting the data you want.

Update: By the way, IO::Socket::INET greatly simplifies the socket creation.

use IO::Socket::INET qw( );

my $sock = IO::Socket::INET->new(
    Proto    => 'tcp',
    PeerHost => 'axtcnr:6540',
)
    or die("Can't connect to axtcnr:6540: $!\n");
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($sock is already set to autoflush.)