The ISOUSB211 device supports Suspend low power state, also called L2 state in the USB 2.0 Link Power Management engineering change notice (ECN). Suspend mode is detected if the bus stays in the LS/FS/HS idle state for more than 3 ms. When Suspend is detected from LS and FS idle state, the ISOUSB211 continues in the LS or FS idle state, at the same time reducing internal power consumption. If Suspend is detected from HS idle state, the ISOSUB211 detects the DS port transition to FS idle state (FS J), and reflects this upstream, while disabling all high-speed circuits to reduce power consumption. The transition to the L2 low-power mode is completed within 10 ms.

Exit from L2 occurs through either Resume signaling from the host, on the upstream facing side of ISOUSB211, or Remote Wake signaling from the peripheral on the downstream facing side of ISOUSB211 followed by Resume signaling from the host/hub on the upstream facing side. Start of Resume or Wake are signaled by a ‘K’ state by the host or the device respectively. The end of resume is signalled by the host by driving two low-speed bit times of SE0 followed by a 'J' state. If the port was operating in high speed before entering the low power state, end of resume is signaled by the host by transitioning to the high speed idle state. ISOUSB211 is able to replicate the resume and wake signaling appropriately both upstream and downstream. After Resume/Wake signaling the device returns to LS, FS or HS idle state depending on the state it was in before entering the L2 state.