If the Epivalley data modem is not installed along with Tata Photon +, it means that the installation package provided by Tata Teleservices doesn't contain the driver for your modem. For this reason, I suggest you use Google search engine to find and download the driver. Also, you can use a driver identifier from Software Informer database. Once you found and downloaded the driver, connect the modem to your computer and press Windows + R key combination. Type devmgmt.msc and click OK. Expand the Network Adapters list, right-click the driver and select Update Driver Software. Use the Browse option to navigate to the downloaded package, select the driver and install it following the on-screen instructions.