No. I have both as well and use the M5350 when away from home, and also at home as a fall-back if my existing ISP & Router has a glitch. The M5350 will be setup to broadcast a different wireless nrtwork/SSID to your existing router - so just make sure your pc/tablet/phone is connecting to the right one as relevant. I found this device easy to setup and use, so happily recommend it. I use it with a T-Mobile rolling 30-day data SIM for the 3G connection.