@lesm,

Connecting your Printer to your modem would not allow for your devices to use the printer, as the printer is outside the control of your Archer Router.

The only way in which this could work is if your TD-8968 is the router of your network, supports a Print Server function, and the AX3000 is configured as an AP - however you will be limited by the features of the older DSL modem.

Unfortunately, with most printers moving to wireless-based connections, print servers for USB printers are not commonly found at a consumer router level. If your printer has wireless capabilities, you can configure the printer that way.

Otherwise, there are adapters out there that you can plug your printer into. The adapters have a print server running and will allow you to connect your printer to your network via an ethernet cable wired into your network. Your Devices should then be able to see the printer and use it normally, however; your mileage may vary due to the amount of variation between printers, adapters, and features.