Perhaps ord and chr? Or maybe not turn the unpack'd value right back into a character?

$ perl -lE 'say join( q{,}, unpack( "C*", qq{Hello} ) )'
72,101,108,108,111
$ perl -lE 'say join( q{,}, map ord, split(q{},qq{Hello}) )'
72,101,108,108,111
$ perl -lE 'say pack( "C*", 72, 101, 108, 108, 111 )'
Hello
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