The Catalyst 6000 family 8-port T1/E1 PSTN interface module is a high-density, 8-port, T1/E1 Voice over IP (VoIP) module that can support digital T1/E1 connectivity to the Public Switched Telephone Network (PSTN) or transcoding and conferencing. The module requires an IP address, is registered with Cisco CallManager in its domain, and is managed by Cisco CallManager.Hot swapping lets you remove and replace the 8-port PSTN interface module while the system is operating. When the system detects that a module has been installed or removed, it automatically runs diagnostic and discovery routines, acknowledges the presence or absence of the module, and resumes system operation without any user intervention. Environmental monitoring of chassis components provides early warning indications of possible component failure to ensure safe and reliable system operation and avoid network interruptions.