WS-C3524-PWR-XL-EN comparability with CP 7821

[ByungchulShin1013]

Hello!

I have connected WS-C3524-PWR-XL-EN and CP 7821 using PoE. According to their datasheet, they should work but CP 7821 doesn't turn on the power.

3524's version is Version 12.0(5)WC13 and cisco WS-C3524-PWR-XL (PowerPC403)

Is there any way to turn on the power of CP 7821 with 3524?

Thanks in advance,

[balaji.bandi]

The Catalyst 3524-PWR XL switch has 24 10/100switched ports with integrated inline power andtwo Gigabit InterfaceConverter (GBIC)-basedGigabit Ethernet ports (See Figure 1). Integratedinline power provides DC current to devices thatcan accept power over traditional unshieldedtwisted pair (UTP) cabling (for example, the Cisco7900 family of Cisco IP phones).

it should work as expected, post the configuration and show power inline  output'

[ByungchulShin1013]

interface FastEthernet0/1
switchport trunk encapsulation dot1q
switchport trunk native vlan xx
switchport trunk allowed vlan x, x, x, xx
switchport mode trunk
switchport voice vlan xxx
switchport priority extend cos 0
spanning-tree portfast

and there is nothing special config regarding of Voice and Power option. Also, there is no available command show power inline output. Perhaps it's because of IOS version.

Thank you,

[balaji.bandi]

I have requested for show running-config to look at what is there global config configured for power, not the interface config.

here is your reference :

power inline

Use the power inline interface configuration command to determine how inline power is applied to the device on the specified Fast Ethernet port of the 3524-PWR-XL switch. Use the no form of this command to return the setting to its default.

power inline {auto | never}

no power inline

Syntax Description

auto	Automatically detect and power inline devices.
never	Never apply inline power.

Defaults

Power is applied when a telephone is detected on the port (auto).

Command Modes

Interface configuration

Command History

Release	Modification
12.0(5)XU	This command was first introduced.

Examples

This example shows how to always apply power to the port:

Switch(config-if)# power inline auto

 

You can verify the previous command by entering the show power inline privileged EXEC command.

Related Commands

Command	Description
show power inline	Displays the power status for the specified port or for all ports.
switchport priority extend	Determines how the telephone connected to the specified port handles priority traffic received on its incoming port.
switchport voice vlan	Configures the voice VLAN on the port.

[ByungchulShin1013]

Hello BB,

The power inline setting is all auto. CP 7942G is working with the switch correctly but not CP 7821.

As far as I know, CP 7821 supports 802.3af and at and 3524 supports 802.3af. So, I think it should work.

Even, CP 7942G needs power more than CP 7821. Perhaps, there is something hidden.....

And there is no global configuration regarding Power and PoE in the running-config.

Thank you,

[Leo Laohoo]

Try different cables.
If Pair "C" is faulty then the switch won't provide power.

[ByungchulShin1013]

Hello Leo,

I have tested with CP 7942 and the switch successfully provided the power. However, not CP 7821.

So weird.... CP 7821 power consumption is less than CP 7942.....

[balaji.bandi]

Maybe this odd situtaiton, is the Phone working status before or tested with other switch if you got a chance?

[ByungchulShin1013]

CP 7942G was already connected to port 1 and I have connected 7821 to port 1 after unplugging CP 7942G for a replacement.

Also, I have tested CP 7821 with another 3524 and it didn't work. And then tested with 3650 and CP 7821 had power on.

So, CP 7821 is working with 3650 but not 3524.

[Leo Laohoo]

Post the config of the port.

[ByungchulShin1013]

interface FastEthernet0/1
switchport trunk encapsulation dot1q
switchport trunk native vlan xx
switchport trunk allowed vlan x, x, x, xx
switchport mode trunk
switchport voice vlan xxx
switchport priority extend cos 0
spanning-tree portfast

and there is nothing special config regarding of Voice and Power option. Also, there is no available command show power inline output. Perhaps it's because of IOS version.

[balaji.bandi]

Phone 78XX - The phone is an interoperable IEEE 802.3af PoE (Class 1 device)

Phone 79XX - Supports IEEE 802.3af PoE (Class 2)

After reading some documents, i found it is different between this PoE support. I believe Switch was the old standard of IEEE standard, as per the document, i do not have both these models to test for you, maybe someone gives hand who can offer a test.

When you connect another switch working, what is power consumption in the port?

can you post the output working switch, also connect to not working and post the same output.

[ByungchulShin1013]

Result of 3524

Interface             ILP-Device Power
-------------------- ---------- -----
FastEthernet0/1      yes           yes
FastEthernet0/2   unknown      no

Result of 3650

Interface   Admin Oper Power        Device            Class   Max
                                   (Watts)
--------- ------ ---------- ------- ------------------- ----- ----

Gi1/0/29    auto    on     3.2     IP Phone 7821         1      30.0
Gi1/0/30    auto    on     6.3     IP Phone 7942        n/a    30.0

There is no option to see how much power consumes in 3524.