While most of existing VOIP systems (specially asterisk based ones) move from the Traditional PBX era to the VOIP era; Zenda moves the Traditional PBX itself to the VOIP era.

With Zenda, you can still use all the long run, well structured, professionally categorized PBX features/services within your VOIP server, so that you can gain the power of the two era with one server.

Zenda is designed from day one with this goal in mind, and put all services, apps, and tools to achieve it.

Yes, it’s free. You can download, install, register, and start using it (with most features and services) for free, without time limit or other hidden restrictions.

Of course, there are some advanced features/services that require a commercial license; but they are for advanced usage only, and most of small to medium size sites can work perfectly without it and stick with the free license, which is – again – completely FREE.

In addition to the free license model, which you automatically have after registration; there are commercial license models. Right now, the commercial models available are BASIC and SILVER, but in the feature (near feature we hope) there will be another models available (e.g. GOLDEN, DIAMOND, …).

The free model gives you a wide range of unrestricted functionalities, e.g. fully PBX, call recording, voicemail, IVR, DISA, and a simple but so practical reporting tool. And in most cases; that may satisfy your needs.

But in some cases you’ll need to get one of the commercial license models to obtain some extra functionality as following:

You need a BASIC license model to get:

• Advanced reporting engine with more options, templates, and auto report generation (automatic report schedule).
• Agent popup screen for notifications and data entry.
• Supervisor dashboard for live monitoring of agents, calls, statistics, and service level.
• Internal CRM system (up to 20 users) and/or external CRM integration

You need a SILVER license model to get:

• Dialing list service (both auto and predictive dialing)
• Unlimited internal CRM system

The permanent license is activated once and be valid forever without any renewal fees. But the renewal license is activated only for limited time (e.g. one year), and after that it’s automatically deactivated.

When you register a new account; it has 2 holders for your license, one for the permanent and the other for the renewal, and initially permanent holder set to FREE while the renewal set to TRIAL for 60 days, and the actual active license is the higher valid one (which is the TRIAL in the initial case).

When the renewal license expires (either initial TRIAL after 60 days, or one you bought after); your permanent license becomes the only valid license and takes effect.

So for example: 

• During the first 60 days after registering; your account has 1 FREE license as permanent, and 1 TRIAL as renewal. And since TRIAL is higher than FREE; your actual working license will be TRIAL.
• After 60 days; your renewal license (TRIAL) will be expired, and you’ll have only 1 FREE permanent license, so your working license will be FREE.

You can have 2 licenses at the same time, 1 permanent and 1 renewal, and the actual working license will be the highest of them.

If you add a new license, either permanent or renewal; the old one automatically removed and the new one replace it regardless of the state & validity of the old license.

Permanent license can be replaced with a higher one only, while the renewal license can be replaced with a higher one (upgrade) or equal one (expand).

No physical specifications needed for the server machine, you even can use a VIRTUAL machine as well. The machine requirements depends largely on the total number of users (extensions), and the audio payload(s) used (e.g. G711 uses less cpu resources than G729). But your can prepare your machine as follow:

• Processor: Fast enough to fulfill your final number of users and payload types (e.g. CORE I5 minimum)
• RAM: Depends on users count (e.g. 16 GB can cover 10 users)
• HDD: Large enough for your media storage (the system itself need only about 6 GB)

Although Zenda is based on Asterisk framework, and Asterisk itself supportd so many standard IP signaling protocols (e.g. SIP, H323, SCCP, IAX, …); most of these protocols start to be neglected by the hardware manufacturers, and most of those manufacturers focus on the SIP protocols (due to it’s spreading and ease of implementation). So Zenda also decided to ignore all protocols except the SIP, which is the current de-facto standard for all the VOIP telephony world.

Any SIP standard Hardphone and/or Softphone are supported by Zenda.

Note that: some vendor specific hardphones (e.g. CISCO, AVAYA) models need some kind of firmware to become SIP standard. So you can refer to phone vendor itself for these models.

Asterisk, as a framework, supports two ways to do that, Telephony Cards (e.g. Sangoma), and Gateways. But since Gateways is more flexible, and become very stable and more cheaper; Zenda goes with it and neglect the old Telephony Cards.

Any Gateway that support SIP Trunking (almost all of them do) can be used with Zenda system to connect Traditional Trunk Lines (FXO) or even Traditional Phone sets (FXS).

The configuration interface inside Zenda part is abstracted and doesn’t depends on the brand, model of the Gateway; but of course the configuration interface inside the gateway itself related to each brand/model, and you can refer to gateway’s vendor for that.