What is the difference between PVDM and EHWIC?
We are often asked to explain what expansion slots are commonly available on Cisco Routers. Two common types are PVDM and EHWIC.
A Packet Voice Digital Signal (PVDM) is a hardware module that provides digital-signal-processor (DSP) resources to the system. A PVDM module can be populated with one or more DSPs. The DSP resources on a PVDM module provide collaboration services including voice sessions, transcoding sessions, conference sessions, and video.
Two PVDM versions are currently supported: the PVDM2 series modules and the PVDM3 series modules. The Cisco 2800 and 3800 Series platforms support only the PVDM2 modules. The Cisco 2900 and 3900 Series platforms support both the PVDM2 and PVDM3 modules. The PVDM3 modules provide higher density (up to 4 times higher) than the PVDM2s. They also provide improved performance in terms of the number of conference and transcoding sessions supported.
The Cisco High-Speed WAN Interface Card (EHWIC) is an updated and enhanced version of the current HWIC for the Cisco Integrated Services Router Generation 2 (ISR G2). The EHWIC offers greater speeds (up to 800 Mbps bidirectionally) and higher port density than the current HWIC. It also has a third row of pins for increased power to the cards, as well as support for Enhanced Power over Ethernet (EPoE) with up to 20 watts per port. Furthermore, the EHWICs have a connection to the traditional router CPU and the new Multi-Gigabit Fabric (MGF) backplane. EHWICs are available in single-wide and double-wide form factors.
(Single-wide interface cards can only be installed in interface card slots on Cisco 1800 (modular) series, Cisco 2800 series, and Cisco 3800 series routers.
Double-wide interface cards can only be installed in interface card slots on Cisco 1900 series, Cisco 2800 series, Cisco 2900 series, Cisco 3800 series, and Cisco 3900 series routers.)