Help flashing Cisco 7940 with SIP

I recently bought a Cisco 7940 that I now need to convert to SIP. I've read quite a bit about how to go about it and I think I have a handle on it... for the most part. I have 2 different TFTP server programs downloaded. I have all the files set up and ready to go in the TFTP root folder.

The area where I'm having a problem is the DHCP server. I'm in a small office and we run a handful of pcs all with static IPs behind a switch and a router. There's no dedicated DHCP server.

Can I accomplish this by plugging up the phone and a pc to a router and setting it to DHCP mode? I've noticed instructions involving "scope options", etc. Honestly, I don't know what that is.

Can anyone point me in the right direction?

Thanks so much.

chadmw7 :

I recently bought a Cisco 7940 that I now need to convert to SIP. I've read quite a bit about how to go about it and I think I have a handle on it... for the most part. I have 2 different TFTP server programs downloaded. I have all the files set up and ready to go in the TFTP root folder.

Sounds like you've made a good start then - there's a lot of half-tutorials around and I tried to just read them all before getting started.

I documented my endeavours on my Wiki and although it's aimed at the 7960 it's exactly the same for the 7940. It's hopefully worth reading through - http://wiki.siftah.com/Cisco_7960G_IP_Phone_on_Asterisk

chadmw7 :

The area where I'm having a problem is the DHCP server. I'm in a small office and we run a handful of pcs all with static IPs behind a switch and a router. There's no dedicated DHCP server.

I believe it may be possible to hard-configure the IP and network settings for each phone, but you'll still need to setup a TFTP server anyway.

chadmw7 :

Can I accomplish this by plugging up the phone and a pc to a router and setting it to DHCP mode? I've noticed instructions involving "scope options", etc. Honestly, I don't know what that is.

You could use the DHCP from a router, but I expect you'll find you don't have the level of configuration needed from the standard firmware. I'd suggest running OpenWRT or DD-WRT firmware on your router if possible, that would give you the ability to have more configurable TFTP and DHCP services, which you're going to need.

The Cisco hardphones are designed ostensibly to be deployed in an Enterprise environment, hence they're really aimed at users with DHCP and TFTP servers setup.

Good Luck