would be that you have a typical end-of-line type of problem.
$/=280; means readline reads 280 bytes at a time, not lines (so line-ending characters don't matter). 
C:\>perl -e"die unpack q~H*~, $/"
0a at -e line 1.

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In reply to Re^2: how to read data for every 280 character ? by Anonymous Monk
in thread how to read data for every 280 character ? by bh_perl

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