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New Member

Do 7910s really run at 10Mbps half-duplex?

While tracking down a problem which seems to be unique to 7910s, I noticed that all our 7910s autonegotiate 10/half with the 3524s; 7940s and 60s run at 100/full. The 7910 Data Sheet doesn't mention anything about this; are these really half-duplex devices, or can I force 100Mbps/full on the switch?

7 REPLIES
New Member

Re: Do 7910s really run at 10Mbps half-duplex?

michael: yes you are correct they are 10/half. so there are issues with ports on switches and hubs.... marc

New Member

Re: Do 7910s really run at 10Mbps half-duplex?

We don't have those issues, but another transient bug we're trying to trap. I didn't want to confuse the test/trap we've set up, so haven't tried to force the phone to 100/full (or even 10/full), but according to the docs

(http://www.cisco.com/en/US/customer/products/hw/phones/ps379/products_administration_guide_chapter09186a0080080666.html) you _ can_ set it to 100FULL:

Cisco IP Phone 7910

Procedure

--------------------------------------------------------------------------------

Step 1 Press the Settings button.

Step 2 Press 6 to select Network Configuration.

Step 3 Scroll (using the volume up/down keys) to SW Port Configuration.

Step 4 Press * to enter edit mode.

Step 5 Press the volume down button to scroll down through options.

Options are AUTO, 10HALF, 10FULL, 100HALF, and 100FULL.

Step 6 Select an option, then press the volume up button to exit this menu.

Step 7 Press # to save this change.

...however, this wouldn't be the first time the docs have been wrong. I'll try it with another phone and post the results here. (It's a long walk through cold rain today to get another phone, so maybe tomorrow.)

On the _other_ other hand, the label on the phone says "10MBSwitch".

New Member

Re: Do 7910s really run at 10Mbps half-duplex?

7910 is only 10 Mb/half. On the 7910+SW (with pc-port) you can change the speed hd/fd.

Rob

New Member

Re: Do 7910s really run at 10Mbps half-duplex?

I suspected that; thanks. I guess it's no big deal -- in a very early test of VoIP, we ran a 7960 at 10/half on a 24-port 10MB hub shared with 23 active PCs, then via a private FR WAN link to the Internet with no QOS to a remote site. Consensus was the phone sounded like a bad cellphone, but it was usable.

New Member

Re: Do 7910s really run at 10Mbps half-duplex?

Michael: see the following article:

http://www.cisco.com/warp/public/cc/pd/tlhw/prodlit/7910_ds.htm

Depending on the model 7910G and 7910G+SW you either get a 1 port 10T for the phone or a 2 port 10T for phone and a 100T to plug your computer into and run it thru the phone. The 7910 is still only a 10basedT phone.

thanks marc

New Member

Re: Do 7910s really run at 10Mbps half-duplex?

Thanks, Marc... that certainly isn't obvious from reading the article (or any other Cisco documentation, for that matter), but it's good to know. We've got one lab running off a 100Mbs switch (not a 10/100 switch), and if we had elected to install a 7910 there, we might have run into problems. Do you know what forwarding method the switch in the 7910+SW uses? I wonder if that phone would work on a 100Mbs (only) link.

New Member

Re: Do 7910s really run at 10Mbps half-duplex?

For anyone interested... the problem I referred to in my initial post was that several of our 7910s would show up as Not Registered, wwith their displays blank, after a random period of normal operation.

It turns out that when the 3524-PWR-XL goes through a power off/on cycle lasting more than a few seconds, any 7910s attached to and powered by the 3524 will not power up properly unless the switchport is explicitly configured as 10/Half. The phone can only be brought up by unplugging/replugging it, or remotely via a shut/no shut sequence.

Now the question arises: Since a 10Mbps switchport is nontrunking, how do I configure things to ensure proper COS for a 7910? I'm rapidly deciding the 7910 is a sorry excuse for an IP phone.

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