Paging Groups

Advanced IP phone systems allow even small offices to have a fully functioning paging system without using a standalone system. Users can page other users by dialing the paging account and speaking into the phone. Recipients will hear the message from the speaker on their phones.

Paging can be thought of as a one-way audio session, as opposed to intercom, which features two-way audio for one-to-one communication. Paging allows a single extension to communicate with a few people (unicast paging) or a potentially large group of people (multicast paging).

Several paging groups can be configured on the system so that different audiences can be addressed.

Two types of paging accounts can be configured on the system: Unicast and multicast.

Unicast Paging

Unicast paging is a one-to-one call to each participant in the paging group (i.e., the system establishes a regular call to each extension through standard SIP calling). While this is usually fine for a small group, it can be burdensome for larger paging groups, since it ties up a lot of resources in the PBX. A paging group with 20 extensions is essentially a 20-person conference call. Due to the increased demand on CPU performance, this unicast paging is appropriate for paging groups consisting of no more than ten extensions.

Multicast Paging

A multicast page is essentially a predefined broadcast address that the phones or SIP user agents are programmed to listen to. Each phone can be configured to listen to as many as 10 different multicast IP addresses.

The advantage of a multicast page is that only one SIP session is established between the originator and the PBX. Subsequently, the PBX sends only one RTP stream to the multicast group on which the phones are listening. If there are 100 phones listening on a multicast page, it is equivalent to a single phone call instead of a 100-party conference call. This makes multicast paging suitable for groups that number in the thousands.

Creating a Paging Group

  • Go to your selected domain in the Vodia PBX web interface.
  • Go to agent groups by clicking on Paging Groups under Accounts as shown above.
  • A pop up window would give you a chance to enter the details in the new GUI.
  • On top, click the tab Create to create a new paging group.
  • In the Account Name field, enter an extension number and/or alias. When entering an alias in addition to an extension number, use the following syntax: 667/668.
    Note: If you use a space instead of a slash (667 668), you will create two separate accounts that will be unrelated to each other.
  • To create multiple accounts at the same time, use a space between the numbers: 667 668 669
  • Press .
  • The paging group(s) will be created which you can see in the “paging group list” or in “all accounts list”, where you can enter each paging group just by clicking it, in order to modify it if you want, as explained below.

Using the Paging Account from a Phone

Using the paging account is pretty straightforward.

  • If you are in live playback mode, dial the paging account number and start speaking. When you hangup, the paging stops. If there was a maximum paging duration setup, the system will cut off the paging at that time.
  • If you are in recorded playback mode, dial the paging account number and start speaking after the beep. If you want to re-record the message, press '*' during the recording (requires version 5 or higher). After you hangup, the message is scheduled for playback and will be played back as soon as possible.

Setting up the Paging Account

  • Account Number(s): This field takes extension number(s) and/or DID number(s). The number of DIDs that can be entered into this field is unlimited. This information can be changed at any time.
  • Display Name: The display name will be used to identify the source of the call. SIP phones will display this text in the display area. The Accounts page will list the display name next to the account number:
  • Streaming Mode: This setting allows you to determine how your paging group will be set up:
    • Unicast (SIP): When using unicast mode, you’ll need to provide a list of destination numbers for your paging group in the next setting (Destination). With unicast paging, the system initiates a call to all extensions listed, so be sure to limit your paging group to no more than 10 extensions. Unicast paging is not limited to the local area network, so all extensions that are connected to the system will be paged regardless of location.
    • Multicast: Multicast mode allows you to designate a single IP address as your paging group and create paging groups that encompass entire organizations without taxing bandwidth (the end systems are unaware who the members of the multicast group are and do not send SIP signaling to the individual paging devices). When you page the group using this method, all devices configured to listen on the same multicast IP address will go into paging mode as soon as they receive RTP traffic on that port.
  • Destination: Enter a group of extension numbers into this field. When using the multicast mode, these extension numbers automatically become part of the paging group specified in the Multicast-Address field, as long as the extensions are registered to phones that have been configured for plug and play. Once the paging account has been configured, the phone will pick up the IP address that has been set in the paging account, indicating that the phone is now part of that “paging group.” (To verify that the IP address has been configured to the phone, go to the phone’s web interface, click Advanced > SIP RTP, then scroll to the bottom of the page). A single phone can be configured to listen in on up to ten IP addresses or paging groups. In the example shown below, the phone has been configured to listen in on four multicast IP addresses.
  • Source: List the extensions that are allowed to page this group. Enter a star (*) to give access to all extensions.
  • Multicast-Address: Enter a multicast address into this field. The IP address range for multicast addresses is 224.0.0.0–239.255.255.255. When using a traditional paging system, use the IP address of the paging device (e.g., (192.x.x.x).
  • Codec: The system comes with G.711 and is free. Other codecs, such as G.729, require a fee due to the royalties associated with them.
  • Playback method: The playback method feature can operate in three different modes:
    • Live playback: This mode allows you to send a page in real time. With this mode, you pick up the phone, dial the paging account number, and start speaking/paging. All interested parties will hear the page.
    • Play recorded message: This mode has a store-and-forward mechanism and requires that you record the message before sending it to the interested parties. With this mode, you pick up the phone, dial the paging account number, and start speaking. The system will record the message once you hang up and will send it to the interested parties.
    • Play the associated wav file: This mode plays the associated wav file, which can be chosen (the option to choose the wav file appears) once this option is selected.
  • Permissions to monitor this account: This setting defines which extensions may monitor the status of this account, for example with a BLF button. By default, all extensions are allowed to see the status of an account. The setting is a list of extensions and wildcard patterns, seperated by space characters. If the list element contains a "np" (no pickup) flag after a colon seperator, then the monitoring will show only if the account is idle or busy. An example for this settings would be "41 42 5* 61:np 70*:np". The "np" flag was introduced in version 61.
  • Maximum page duration: Time limit on the duration of the page, after which it is disconnected automatically.