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SPA504G Shared line

I am planning on purchasing 4 SPA504G IP phones but want to confirm that they will share a single DID.  All phones will be registered directly with my VOIP provider.  Can I set them up so that when a call comes in, all phones ring and one person can place a call on hold and have a different phone continue the call?  I nknow there is a share extension function, but was not sure if it will work when the phones are connected directly to the VOIP provider.  It also appears that ext_1 cannot be set as shared.  Any help would be appreciated.

Cisco Employee


I think you should direct that question to your VOIP provider, if multiple devices can be registered to an account an share a single DID.

Typically the last device to register into the VOIP account would be the device to send the call to. Last in first out.

It sounds like you are looking for a hosted solution to allow multiple SIP devices to share the same DID. The logic to handle this is with the VOIP provider or a PBX device as a UC540 or UC320W.




Thanks for the reply Randy.  I did check with my VOIP provider and they indicated that I could set up sub accounts and then create a ring group consisting of the different sub accounts which the DID points to.  Each device gets registered to a different sub account and theoretically all phones ring.  I guess my question is whether or not the SPA504 phones can share a line in this manner and how I do it. 



Yes the 504 supports shared lines in that they all register to the same did.  IT looks like your voip provider does not allow that and requires you to get 5 lines, 1 for each physical phone and 1 as a ring group to ring the other phones. 

This approch requires you to do a transfer to send the call to a different phone vs if they all register with the same number you put hold on 1 phone and push the line button on another.

with a 4 line phone you will be able to do BLF which will allow you to pick up calls that are ringinng on another phone and see if someone is on another line.

It sounds like you are a retail shop and want a key system type config.  It is all based on your VOIP provider.

When we do something like this we charge a line charge for calls then an access charge for each extra phone that registers to the DID