Update: Note to self, don't come to PM first thing in the morning. I missed the "must match pair" part of the question. Just change .* to .*? in your regexp and ignore what follows in this post. It's still neat reading, though :)

\|i([^|]*).*\|l([^|]* means match everything from the first |i barcode to the last |l homeloc, inclusively. Try replacing your while with the one below:

$line = '|i1234|lABCD|i5678|i90|lBOO';

while($line =~ /\|i([^|]*)|\|l([^|]*)/g) {
   print("barcode: $1\n") if (defined($1));
   print("homeloc: $2\n") if (defined($2));
}

__END__
output
======
barcode: 1234
homeloc: ABCD
barcode: 5678
barcode: 90
homeloc: BOO
[download]

Here's another nice solution that uses m/\G.../gc

$line = '|i1234|lABCD|i5678|i90|lBOO';

for ($line) {
   /\G \|i     ([^|]*) /gcx && do { print "barcode: $1\n";  redo; };
   /\G \|l     ([^|]*) /gcx && do { print "homeloc: $1\n";  redo; };
   /\G \|[^il]  [^|]*  /gcx && do { redo; }; # skip bad stuff
}

__END__
output
======
barcode: 1234
homeloc: ABCD
barcode: 5678
barcode: 90
homeloc: BOO
[download]