First generation hardware may generally be identified by the version number on the label located under the router. For the DSL-500 (modem/router only), Version C2 generally indicates first generation and for the DSL-504 (modem/router/switch), Version A2 generally indicates first generation.

First generation hardware includes a 9-pin serial port for serial console access.

The DSL-500G and DSL-504G are incompatible (ie different hardware) models released in early 2004.

See also Second generation hardware