T644DTN MONO LASER 32K TONER 20G2206. The Fast Ethernet-ready Lexmark T644dtn provides outstanding value with a standard 514 MHz processor- 128MB memory- duplex unit and 1100-sheet input. With its optional wireless- security-minded options and special applications and paper handling features- the Lexmark T644 is easily adapted to a workgroup?s needs. Its print speed of up to 50 ppm on letter-size paper and a time to first page as fast as 8.5 seconds make this a great workgroup solution.