Cisco 7911G Hardware Info

Here is some hardware information on the Cisco 7911G VoIP phones that might be useful to someone down the line thinking of integrating the phones into a HSMM-MESHÔ system.

• The power connector not same as the WRT54 series routers.  The DC power jack is a 5.5mm OD/2.5mm ID jack rather than the 5.5/2mm of the WRT routers.
• It also runs off of the POE, which is 48V rather than 12V like some polycom phones.
• The PoE chip is a TPS2375/2377 which according to the datasheet states it needs at least 30V to start power.  In experiments, I found that the phone won't turn on until at least 34V is presented to the DC power jack.  Using PoE over the Ethernet cable, it requires at least 36V to turn on.
• PoE does not appear to care what DC polarity is on pins 3/4 and 7/8, either configuration worked for me