View ds2505 datasheet:

DS2505 16-kbit Add-Only Memory www.dalsemi.com FEATURES PIN ASSIGNMENT 16384 bits Electrically Programmable Read TSOC PACKAGE TO-92 Only Memory (EPROM) communicates with 1 6 GND NC DALLAS the economy of one signal plus ground DS2505 2 5 DATA NC Unique, factory-lasered and tested 64-bit 3 4 NC NC registration number (8-bit family code + Top View 48-bit serial number + 8-bit CRC tester) 3.7 X 4.0 X 1.5 mm assures absolute traceability because no two parts are alike Built-in multidrop controller ensures compatibility with other 1-Wire Net Side View products See Mech. EPROM partitioned into sixty-four 256-bit Drawing Section pages for randomly accessing packetized data records Each memory page can be permanently write- protected to prevent tampering