The cisco 1921 router features two onboard gigabit ethernet (ge) rj-45 lan/wan ports (ge0/0 and ge0/1), alongside two enhanced high-speed wan interface card (ehwic) slots for expansion. it also includes usb, serial console, and auxiliary ports for management.
onboard ports & slots
integrated ethernet ports: 2x rj-45 mbps gigabit ethernet ports (labeled ge0/0, ge0/1).
ehwic slots: 2 slots, which can support ehwic, hwic, wic, or vwic modules (e.g., for t1/e1, serial, or fxs/fxo connections).
doublewide ehwic slots: 1 slot (using a doublewide module consumes both ehwic slots).
usb console port: 1x type-b mini-usb port for management.
serial console port: 1x rj-45 serial port.
auxiliary port: 1x rj-45 serial port.
usb 2.0 type-a ports: 2x type-a usb 2.0 ports for external storage or security tokens.