Hello snowmaker1948

                                      T25 is just a voice cable modem so when you get disconnected from the WIFI network you need to check on the router connected to the modem and make changes on the router interface to configure the WIFI. If this is on the T25 modem you need to  please check for the light status on the modem if the power on the modem goes off then you can try changing power outlet or power cable then check the connection or only other lights goes off then we would suggest you to check the cable signal so please follow the steps mentioned on the below link.

                         http://arris.force.com/consumers/articles/General_FAQs/T25-Cable-Signal-Levels

            What we are checking here is the way the signal comes from out to inside the home. There are some important things that should be within a specific range in order for the internet to work properly.

First, the SNR should be above 33 on all of them. The downstream power should always be between -15 and +15. The closer to 0 the better connection. Finally, your upstream power should always be between +45 and +51

On all of those values you should not have more than 3 decibels (or dB) between the lowest and the highest

By having the values in less than that, your device will have interrupted connection, slow or no connection at all.