This field (also known as the Class field) specifies the transfer speed of the device used in establishing the communication link. It can contain a letter and speed (for example, C1200, D1200) to differentiate between classes of dialers (refer to "Class Field").
Some devices can be used at any speed, so the keyword Any can be used. This field must match the Class field in the associated Devices file entry as shown in Example 12-3:
File Name System-Name Time Type Speed Phone Chap-Script Systems eagle Any ACU, g D1200 NY3251 ogin: nuucp ssword: Oakgrass Device ACU tty11 -- D1200 penril