There are three flavors of Documation interfaces: parallel differential, parallel single-ended and serial (Cardamation). I believe the M1000 only came with the differential interface. I have an HP-branded M600 (HP2983A) and it also has the differential interface. I'm in the process of building a Documation to USB interface based on a Ubicom/Scenix microcontroller and the FTDI parallel- to-USB chip. Have the parts but haven't had time to get started on construction. I'll post the schematics and code hopefully within a month. Dang it Sellam, your M1000 slipped under my ebay search radar because it's a "ballot card reader" not a "punched card reader." Brian =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- _| _| _| Brian Knittel _| _| _| Quarterbyte Systems, Inc. _| _| _| Tel: 1-510-559-7930 _| _| _| Fax: 1-510-525-6889 _| _| _| Email: brian(a)quarterbyte.com _| _| _| http://www.quarterbyte.com