A system for integrating a wireless network with wired field devices includes a field unit that communicates with the wired field devices using a first wired field device protocol. A gateway wirelessly communicates with the field unit and communicates over a network using one or more second wired field device protocols. The gateway also converts between the first wired field device protocol and the one or more second wired field device protocols. The gateway could further permit access to the wired field devices by a component of the process control system (such as a process controller, asset management tool, or configuration tool) that does not support the first wired field device protocol. At least one of the field unit and the gateway could appear as a multiplexer or linking device to the component of the process control system, such as a HART multiplexer or a Foundation Fieldbus or Profibus linking device.