Is the Push feature to talk in the box with UC 500 and 7925 or 7921 Phones or I need to purchase some Third Party XML application?

[lzuniga99]

Hi Guys, I was checking documentation about 7921 and 7925 about the push to talk feature and they do reference to an XML application, but is not clear if this is feature is a Thirparty software I should buy, or if it comes included with UC-540 or the phones.

Any of you have some experience with this feature, using the Cisco Wireless phones as a radio or walkie talkie replacement?

I  have a customer with the following scenario :

• 12 Casino Sites the most of then connected by fiber.
• Each site has its own pbx.
• At this moment the use the RoIp technology with  Raytheon NXU-2A, to convert the radio signals to Ip and transfer radio comunications over the network in one site., the employees need to carry an analog phone and a radio http://www.raytheon.com/capabilities/products/nxu_2a/index.html.
• They want to implenment UC-500 in each site to provide voip, pbx replacement, and replace the radios with wireless Ip Phones with push to talk enabled.
• the users on each site are organized in groups, so al group members can listen the members in that group when tey push to talk.
• At main site there is a User that belongs to the remote group, this user monitors all the comunications at the group that he belongs.
• The main site has a Cisco 2811 with voice enabled (CME) and some Cisco Phones.

I have the following concerns about this scenario, so if any off you have some experience with push to talk, or similar scenarios feedback will be appreciated:

1. Do i need to purchase some extra software to implement push to talk or it comes inside the box, I just found how to configure or how the implement in this support comunity, but nothing is mentioned about my concern.
2. There is a maximum number of phones that can belong to a push to talk group? or per site?
3. Is this push to talk enough robust and high disponibility to replace the radios?
4. If the fiber link fails, I should be able to send push to talk conversations over the wan via vpn to main site, it will work?
5. If i have 11 sites with UC-540  all those UC-540 can register or interconect with the CME at the main site or there is a limit?

Feed back or suggestions will be apreciated

Best Regards,

Laurence.