07-09-2009 09:13 AM - edited 03-15-2019 06:53 PM
Topology: 3550 Switch -- 2821 Voice Gateway -- WAN -- CallManager 6.1(3)
7937 IP Phone does not properly boot.to the network. Switchport configuration is thus:
sw access vlan 102 <---102 is voice vlan
sw mode access
duplex half
speed 10
All other IP Phones (7931) on the switch can connect and boot properly using the following config
sw mode dyn desirable
sw voice vlan 102
Spanning the interface that the 7937 is using and performing traffic capture, I see no DCHP requests from the 7937 whatsoever. In fact, there is no traffic being generated by the phone at all.
Additionally, the phones display does not show the Cisco logo
Additionally, the 3550 switchport interface cycles between up/up and up/down
Any suggestions out there? Could this be a bad phone (RMA)?
Thanks!
07-09-2009 11:43 AM
Hi Robert,
I believe the problem here is that the 7937 requires 802.3af PoE and the 3550 only supports Cisco Pre-standard PoE;
Q. Does the Cisco Catalyst 3550-24 PWR Switch support the 802.3af inline power standard?
A. No, this switch supports Cisco Pre-Standard Power over Ethernet. The Catalyst 3750 Series and Catalyst 3560 Series support the Cisco Pre-Standard Power over Ethernet and IEEE 802.3af Power over Ethernet.
http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps646/prod_qas09186a00800913d3.html
Hope this helps!
Rob
07-10-2009 10:14 AM
The phone does get lit up during this process, so it is receiving some power. However, I have, indeed, verified that there is a power standard mismatch.
I'll try a brick and see if that resolves this. I did not think to check the differing power standards since I was getting lights on the phone.
07-28-2009 07:54 PM
Robert, are you plugging ip phones into hubs again?! :)
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