#! perl
use strict;
use warnings;

my $string = qq{"Tap Rackmount for 3 units\x0A","USR4500-RMK         "\x0D\x0A};

print "Before:\n>>>$string<<<\n";

#    Dec Hex  Oct
# LF  10  0A  012
# CR  13  0D  015

$string =~ s/ (?<!\x0D) \x0A //gx;

print "After:\n>>>$string<<<\n";