I did a factory reset to 504. Upon restarting, the key line LEDs light up green and all 4 lock on the L1 and the phone works regularly: 9 on L1 - 8 L2 etc. Entering the 504 web page I saw that in ext 1 in proxy and registration there is the proxy of the pbx 9000 while in ext 2, 3 and 4 the field is empty.
No way with factory default. It mean something/someone has configured the phone. I assume it's SPA9000 via a provisioning mechanism. Based on your description, there's only Ext1 configured and all line keys are bound to it. I'm unsure about the meaning "phone works regularly". It may mean incoming calls, outgoing calls or both. As you didn't claimed success, it seems not all things works regularly in this configuration.
I inserted ip of 9000 in ext 2, 3 and 4-
It's not just about IP. I assume you copied IP, port and login credentials. OK, you have four identical clients connected to the same account of SPA9000 (assuming SPA9000 allows multiple logins with same credentials - e.g. shared line). But whats the goal of such configuration ? It's still the same SIP accounts used four times. Imagine it's analog line - your configuration is like four analog phones connected to the same wire in parallel. Still assuming the SPA9000 allows multiple registration for same account (so called shared line).
then I went to Phone and in Line key 2, 3, 4 I changed extension from 1 to 2,3,4 but in Share Call Appearance and in Extended Function I don't know what to put.
Forget extended line for now. It's for advanced function and it's not good time to speak about them until basic will work.
As all extensions are sharing the same line, all four extensions are sharing the same line. Thus Share Call Appearance should be "Shared".
Note there qre two settings related to share/private accounts. The one is Ext N->Share Ext and the second is on Phone tab. Both settings needs to be set to "share" to have shared line.
But I'm commenting your current configuration. It seems to be inappropriate for the declared goal.
You need no four phones sharing the same line. You need to have four independent lines. While IP and port can be shared (as you have one call control device - the SPA9000) every Ext N needs to have own credentials. And Share Call Appearance (as well as Ext N->Share ext) should be set to "private".
But it's not about configuration of SPA504G, it's about configuration of SPA9000. Well, it's about configuration of SPA504G as well, but such configuration is just configuration of SIP clients connected to SPA9000. So the SPA9000 needs to be configured first.
I'd like to tell 504 to use the 9000 as a server. I know I'm wrong, but unfortunately I don't know any Cisco technician who can help me in the configuration.
SPA9000 is 5 years past End-of-Support (and 9 years past End-Of-Sale). No Cisco support will help you.
If you bought it now, you must be enthusiast. You have nice piece of old equipment to play with.
So sorry, I can't help you with it as I meet no SPA9000 ever. I decided not to use Cisco's proprietary call control devices for our installations (the lack of long term support has been one of the reason), We are using just Asterisk instead.
May be someone else will advise you here, but SPA9000 is so old and there may be no one familiar with. Especially in this (closed) thread. If you will ask for help with SPA9000, create new thread mentioning SPA9000 in the title.
