Corporate IP telephony: moving from old analog lines to a VoIP system

Many companies in Azerbaijan still run analog phone lines installed years ago: each branch has its own number, internal calls between sites are clumsy, and every new desk means pulling another cable. As a business grows, this model becomes hard to manage. IP telephony (VoIP) carries voice over your existing data network instead of a separate telephone wiring, unifying every office into a single communication system. This article explains when moving to a corporate phone system makes sense, what it requires, and how ONYX delivers it in real projects.

What VoIP is and how it differs from traditional telephony

In a classic analog system, each phone is physically wired to a central exchange over its own line. VoIP converts voice into a digital signal and carries it over the same corporate network — the infrastructure that already runs your computers also serves your phones.

The practical advantages are concrete. Opening a new desk no longer requires a dedicated phone line — an existing network socket is enough. Calls between branches travel as internal traffic, so spending on long-distance and international carrier calls drops in a predictable way. At the same time, the entire system is managed from a central console.

Unified number plan and extensions

The biggest value of corporate IP telephony lies in a single numbering plan: all offices and branches merge into one logical phone system.

This means every employee gets a short extension, and the whole team can reach one another by these numbers regardless of which branch they sit in. To the customer, the company appears as a single number while internal calls are routed automatically in the background.

Network readiness: the foundation of quality

The quality of IP telephony depends directly on the readiness of the network. Voice is real-time traffic — any delay or loss is heard immediately.

For this reason the state of the network must be assessed before migration. The concept of QoS (Quality of Service) is key here: this mechanism gives voice traffic priority on the network so that file downloads or other data flows sharing the same link do not degrade the conversation. It calls for reliable switches, properly configured VLANs and sufficient bandwidth.

Connecting branches into one network

To unite the phone systems of geographically separate branches, they must sit on one secure network. In the MobilGroup project ONYX connected 5 branches and 120 users over a site-to-site VPN — an architecture that also lays the groundwork for inter-branch internal calls to work within a single system. Our services cover every stage, from building the network to configuring telephony.

Real experience: Gazprom Azerbaijan

Corporate IP telephony is not a theoretical topic for ONYX — we have deployed it on a large scale.

For Gazprom Azerbaijan, ONYX built the network on Cisco switches and routers and deployed a Cisco IP telephony system. This is a real example of how a voice solution works when it is built on a reliable corporate data network: the same Cisco infrastructure serves both data and voice traffic. You can read more about our vendor choices and integration experience on our partners page.

When you should switch

Not every company is ready to migrate at the same moment. The following signs indicate that the time for IP telephony has come.

• You have several branches and their phone systems are separate from one another.
• You open new desks often and pulling a line each time takes time.
• Long-distance or international carrier call costs are high.
• You need flexible control to route customer calls correctly (IVR, queues).
• Your old analog exchange is no longer supported and spare parts are hard to find.

For most businesses the sensible path is a phased migration: first the network is prepared, then telephony is piloted in one department, and only after that rolled out company-wide. This approach makes the switch possible without halting operations. You can explore our broader business solutions too.