Maybe your router have QoS features and give a high % of bandwidth to your phone conections, blades use getwork protocol and need more bandwidth, are you using a stratum proxy in your lan? or are you connecting blades with getwork to pools?
Regards
mining_proxy.exe -o mint.bitminter.com -sp 3333 -gp 8332
and my router is
Linksys E4200
Maybe you can start disabling QoS, I read some theads about issues with QoS in this router