Configuring and troubleshooting of Cisco IP phones and Third-party phones.  Moving, Adding, Change and Deleting Extensions (MACD).  Troubleshooting of IP Phone registration issues.  Configuration of user features such as speed dial, call forwarding, transfer, call park, call pickup, call forward all, Extension mobility, SNR etc.  Configuration of phone button template and softkey template.  Management of Class of Service using Partitions and CSS.  Monitoring and troubleshooting of voice interfaces: FXS, FXO, ISDN PRI E1/T1.  Monitoring and troubleshooting of SRST and call signalling protocols like H323, MGCP and SIP.  Management of Voice mail users (CUC).