An external-facing portal generally provides to users a light desktop, which includes a light framework page. Content is displayed within the light framework page in order to reduce the resources that must be transferred.
For users who require accessibility, create a display rule that provides the standard desktop (and standard framework page) to these users. For example, you could provide an alternative URL – such as http://myServer:50000/irj/portal/accessible – and create a display rule that provides the standard desktop to users who enter this URL.
For more information on an external-facing portal, go to Implementing an External-Facing Portal.