BLF Limitations

Some phones will struggle to handle multiple BLFs, especially if there is significant activity on the monitored lines. It is important to remember that with a simultaneous ring situation, the phone will receive an update for every monitored line.

Poly Phones

Per Poly, adding BLF beyond the number of line keys present on the phone may cause the phone to slow down.

Testing done at Nextiva shows that having monitored users on simultaneous ring does cause Poly phones to be slow to respond. If the users monitored are not simultaneously ringing, you can add up to 30 BLF without seeing a significant change in performance.

Panasonic Phones

The Panasonic UTG 200B has a flex key limit of 24. This limit means only 24 BLF can be assigned to this phone.