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320W is SIP only or Analog only, not both?

Just before ordering a 320W for a new office my Cisco reseller told me that because of dial pattern issues that the 320W has to be configured for all analog lines, or all SIP lines. 

It's appearently not possible have both at the same time.

I decided to go with all analog lines for now, but this was a big disappointment.  I can't afford the 500 series device that was recommended.

I got to wondering, if dial patterns are the issue could a 320W be configured to accept incoming calls from a SIP connection, but not dial out at all on it?  That would work fine for our operation.

Is there any plan to update the 320W firmware to support this feature?  If such an update is not planned, Cisco really should update the 320W data sheet to make this limitation clear.  Both me and my reseller didn't realize this was a problem until very late in the game.


Christopher Edgeworth
Frequent Contributor

Hi Jim,

I was wondering if you could elaborate on the dial plan issue.  We have a number of customers using both FXO and SIP trunks on the same system.  One thing they might be referring to is if you want key system behavior you need to use FXO.  But in a PBX behavior both SIP and FXO can work on the same system.


The system isn't due to be installed for another week.  I'm not sure how they plan to configure it, but I can tell you what I asked for, which I think is about as simple a system as one could have.

We have ordered 5 SPA508 instruments.  We need four incoming lines.  Three of these lines form a hunt group and share a common voicemail box, the fourth line is independant with its on button on the phone and its own voice main.

My original plan was to have two analog lines for the most used two lines, and one SIP for the third line in the hunt group, and a second SIP for the independant line.

We're ok with a 'dial 9 for outside' requirement.

My reseller has told me that this is impossible due to dial plan issues.  I also asked the same question to the chat robot on the Cisco web page and got the same answer "analog or sip, pick one".

This is all I know.

My reseller is adement that in Texas anyway, dial plan issues make it impossible to combine SIP and analog with the 320W, period.   I have to by a 520 if I want that.

So I'm all analog, I have to trust the guy knows what he is talking about.


Hello Jim,

I am presently running the UC320W with three analogue lines and one VOIP SIP trunk and have had no problems with it at all.  We only had one line on the SIP trunk for testing initially, but i have now upped it to two.  I will update the forum if I hit any issues but I don't expect any.




We have many customers that use both. Usually we do something like make "9" the steering digit for SIP, and "8" the steering digit for POTS. At this point we recomment to all of our new customers that want to use SIP to keep one analog line, for the fax machine, as well as a backup line if their internet goes down. This setup works very well, and I would recommend it to anyone selling these for use with SIP.

As I mentioned, in my system I'd like a hunt group of 3 lines for incoming calls.  Is there a problem programing the 320W to have a hunt group with both analog and SIP incoming calls?

Perhaps the other problem is that because of caller id issues I want each of the telephone instrument buttons for these three lines to give a dial tone for that line, and that line only when pressed to call out.

In other words, I want a system that pretty much acts like an 80s style system with a row of lighted buttons on the bottom of the the heavy old fashioned phones. 

Kind of lame I know, but that is what the users and management want.


Thanks to everyone who posted.  I've asked my reseller to have his tech look at this thread and help me understand why I can't use the 320W in a way similar to what Tony and Daniel are doing. 

If we can sort this out before AT&T installs my lines next Wednesday perhaps I can save some bucks by dropping one or two analog lines in favor of SIP lines after all. 

you can have analogue and SIP. But obviously the two can't share the same incoming number. Is this what you were meaning?

For example, if your office has only one telephone number, you have 2 analogue lines and 2 sip trunks, you can make 4 outgoing calls but you can only recieve 2 incoming calls to your office number. Does this make sense?

Thanks Paul.  Perhaps this is our problem.

I want my SPA508 buttons to work like this:

button 1 - when pressed, gives dial tone for analog line 1, when called rings 

this button this hunt group with a specified ringtone,    or if this line is in use, rolls to analog line 2. - this line has our main caller id

button 2- when pressed, gives dial tone for analog line 2, when called rings this hunt group this button with a specified ringtone,

or if this line is in use, rolls to SIP line 3. - this line has our main caller id

button 3 - when pressed, gives dial tone for SIP line 1, when called rings this button

this hunt group  with a specified ringtone, or if this line is in use rolls to analog line 1  - this line has a different caller id than lines 1 and 2, we need to be able to select it specifically for outbound calls. 

(note:  if line three is in use it's ok for users to call out on lines 1 or 2.)

If a call comes in to any of these 3 lines and they are all busy, or if nobody answers, then the call should go to a dedicated voicemail box for this hunt group.

button 4 - when pressed, gives dial tone for SIP line 2, when called rings only button 4 (a different ringtone would be nice). If busy call transfers to a dedicated voice mail box.  In other words, SIP line 2 / button 4 lives in its own little world.

If the 320W can't act like an old mechanical phone and give a dial tone from a specific line just by pressing the button corresponding to that line, then we're ok with using digits to specify  outgoing lines.  Perhaps 'dial 9 for analog lines 1 or 2', 'dial 8 for sip line 1, dial 7 for sip line 2.

On reflection I can see where this may be asking too much of the 320W.  I do hope that users calling out can control which outgoing line they prefer to use.

Jim, it sounds a little complicated to be honest. I don't think you'll be able to do what you want.

If it was me, I'd use all SIP for the first 3 lines and have an analogue for the fourth line (or just use 4 SIPs if you can get rid of the analogue).

Don't use a key system and then you can program the incoming lines pretty much in any way you want. You'll need to do alittle trial and error testing.

Hello Jim,

I have not set it up in this way but it sounds as though you want it set up as a key system, which the UC320W can do. 

I can think of one reason that you would have been told to go with one or the other and that is your phone number.  The SIP and the analogue would have to have different external numbers as a incoming call has to go somewhere first.  e.g. we have one number for our analogue lines and the SIP has a completely different number so our three analogue lines are the only incoming that we advertise.  However you can ask your VOIP provider to show any number you like for outgoing calls.  So when we make an outgoing call on our SIP line and the recipient has caller ID it appears to be coming from the number we have on our analogue lines.

So with three analogue lines and two lines on a sip trunk we can have five active calls, but only a maximum of three of those can be incoming calls, unless we advertise the second phone number.  If you are not trying to achive having all the lines on one number just ignore this.


I can see from the first post that chris says key systems need to be FXO, as I said I have not configure one this way so I bow to his knowledge.

Message was edited by: Tony Stewart, read Chris's post

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