Code to switch from dsl to 3g at certain time of day

Hi, has anyone a suggestion how to code a modem to switch from 3G to DSL at a certain time of day. I am using a D-Link DWR-921. (LEDE not yet installed)

cron is the typical way to execute actions (scripts) repeatedly at a given time of day

Thanks for the pointer Jeff. That would handle the timing. But is there code available to switch between 3G and DSL?

Those things certainly can be controlled, but the details would depend on what exactly you intend by "switch". Do you keep the interfaces up and connected, or just change the routing? Either way, it should be straightforward to execute the proper commands in a script.