There are several ways to use the Duo two-factor authentication and a smartphone is only one option.
Most employees prefer to use their office phone when enrolling a device because it is more convenient to use and they sit at their desk for most of their work. In other instances, an employee doesn’t have a mobile phone, doesn’t have reliable cellular service or prefers not to use their cell phone at work.
It is also possible to enroll more than one device for employees that work from more than one location or travel for work. For example, an employee may have their office phone as the default but they can also add their home phone, a conference room phone or a hotel room phone. Devices can be added and deleted as needed by the employee or an SSO administrator.
A tablet, such as an iPad or a Galaxy Tab, can also be enrolled as a device. This choice requires the free Duo Push mobile app to be downloaded and installed on the device.
An older cell phone can be used in place of a smartphone, too. Similar to a landline, the Duo system calls the cell phone, the employee answers the call and pushes any number key.
The Passcode option is also available to a cell phone that isn’t a smartphone. Choosing this option prompts Duo to send a text message to the enrolled cell phone. This text is a list of 10 Passcodes that can be used from any computer at anytime. While this option does require a cell phone, it is only used to receive the text of Passcodes.