Unified Communications: Integrating Voice, Video, Chat & Presence for Hybrid Work

Before 2020, "unified communications" was a technology industry buzzword that many Bangladesh enterprise IT teams acknowledged in strategy documents but rarely implemented comprehensively. Voice was the PABX. Video was a standalone Polycom unit in the boardroom. Chat was WhatsApp — personal phones, personal accounts, no archiving, no governance. Presence was looking across the office to see if a colleague was at their desk.

Then hybrid work happened. The pandemic forced organisations to enable remote work rapidly, and tools like Microsoft Teams and Zoom became the operational backbone for thousands of Bangladesh enterprises almost overnight. Employees discovered that having voice calls, video, chat, and file sharing in a single platform was dramatically more productive than switching between a phone, an email client, a video conferencing system, and a messaging app.

The challenge now is building a coherent, enterprise-grade UC infrastructure that serves employees whether they are in the Gulshan office, at home in Uttara, travelling in Chittagong, or on a client site in any district of Bangladesh. This article explains what UC means in practice, how Microsoft Teams becomes the unified platform, what Direct Routing integration with your existing telephony means, and what your network needs to support it all.

What Unified Communications Actually Means

Unified Communications (UC) is not a product — it is an approach to communication infrastructure that integrates multiple communication modalities into a single, coherent user experience. The modalities typically included in a UC platform are:

Voice telephony: Making and receiving phone calls to internal extensions and to external PSTN numbers. In a UC context, this means calling from within the UC application (not a separate desk phone), with the call appearing as a UC platform activity.

Video calling and conferencing: One-to-one video calls and multi-party video conferences, scheduled or ad hoc, from within the same UC platform. Screen sharing, whiteboard collaboration, and recording are typically integrated.

Instant messaging and chat: Text-based messaging between individuals and groups, with persistence (chat history accessible across devices and after the session ends). File sharing, link sharing, and emoji reactions within the chat interface.

Presence: Real-time awareness of a colleague's availability status — Available, Busy (on a call), In a Meeting, Away, Do Not Disturb. Presence removes the friction of initiating a call or message to someone who is unavailable, allowing users to make better decisions about communication channel and timing.

Collaboration tools: Shared file storage, real-time document co-editing, task management, and workflow integration within the UC platform. Microsoft Teams' integration with Microsoft 365 (SharePoint, OneDrive, Planner) is the most mature example of this in the Bangladesh enterprise market.

When all these modalities are available in a single application — with unified identity, unified search, unified notification management, and unified device support across desktop and mobile — the user experience improvement is profound. Employees spend less time context-switching between applications and more time on productive work.

Microsoft Teams as the UC Platform of Choice

Microsoft Teams has become the dominant UC platform for Bangladesh enterprises — and globally — primarily because of its deep integration with Microsoft 365, which most large Bangladesh organisations already subscribe to. Teams is included in the Microsoft 365 Business Standard, E3, and E5 subscriptions. If your organisation pays for Microsoft 365, you likely already have Teams licences deployed or available.

Teams as an Internal Collaboration Hub

Teams' core capability — internal chat, video conferencing, file sharing, and collaboration spaces (Teams/Channels) — has become the standard working environment for a large segment of Bangladesh's professional workforce. Project teams organise their work in Teams channels. Management communications go through Teams chat. Document reviews happen in Teams with real-time co-editing in Word and Excel via the Microsoft 365 integration.

For many Bangladesh enterprises, this internal collaboration layer is already mature. The gap is in external communications — particularly voice telephony to external numbers. When an employee needs to call a customer, they switch from Teams to a desk phone or personal mobile. This context switch breaks the UC experience.

Teams Phone System: Extending UC to External Calls

Microsoft Teams Phone System — an add-on licence to Microsoft 365 (included in E5 or purchased separately for E1/E3 users) — adds external PSTN calling capability to Microsoft Teams. With Teams Phone System, employees can make and receive calls to and from any phone number directly within the Teams application.

This is the key capability that completes the UC experience: now voice calls — including external calls to clients and suppliers — are visible in Teams call history, integrated with Teams contacts, and handled with the same interface as internal calls and meetings.

On-Premise PBX Integration with Teams: Direct Routing

For most Bangladesh enterprises, the path to Teams telephony is not starting from scratch. They have an existing IP PBX (Grandstream, Yeastar, Avaya, or others) with existing SIP trunks, existing DID numbers, and existing call centre or IVR configurations. Replacing all of this with Microsoft's Cloud PBX immediately would be disruptive and expensive.

Microsoft Teams Direct Routing provides a more practical path. Direct Routing uses a Session Border Controller (SBC) — a specialised device that interfaces between your existing telephony infrastructure (on-premise IP PBX and SIP trunks) and Microsoft Teams — to route external PSTN calls through Teams while keeping your existing PBX investment operational.

How Direct Routing Works

The SBC sits between your IP PBX and Microsoft Teams:

An employee in Teams makes an external call. Teams routes the call to the SBC.
The SBC translates the Teams SIP signalling into standard SIP and forwards the call to your IP PBX.
The IP PBX routes the call via your SIP trunk to the PSTN and ultimately to the called number.
The return path is identical: incoming PSTN calls arrive at the IP PBX, which forwards them to the SBC, which delivers them to the correct Teams user.

From the employee's perspective, they are making and receiving calls in Teams. From the infrastructure perspective, your existing SIP trunks, existing DID numbers, and existing call routing logic are preserved and functional.

Direct Routing SBCs from AudioCodes, Ribbon (GENBAND), Oracle, and Cisco are Microsoft-certified for Teams Direct Routing. 3CX also offers certified Direct Routing functionality. The SBC can be a hardware appliance or a virtual machine, depending on the scale of your deployment.

Hybrid PBX + Teams: The Bangladesh Transition Path

For Bangladesh enterprises, the practical implementation often looks like this:

Phase 1: Deploy Teams for internal collaboration (chat, video, file sharing). Most employees are already partly there.

Phase 2: Deploy Teams Phone System licences for users who need external calling within Teams. Configure Direct Routing via SBC connected to your existing IP PBX.

Phase 3: Over time, migrate more call handling (IVR, call queues, call recording) to Teams Phone System features, reducing dependency on the on-premise PBX.

Phase 4 (optional): When the on-premise PBX approaches end-of-life, evaluate whether to replace it with Teams Phone System entirely (SBC connecting directly to SIP trunks without a traditional PBX) or to deploy a new on-premise IP PBX.

This phased approach preserves existing investments, manages change at a pace the organisation can absorb, and achieves the UC goal of unified voice-video-chat without a disruptive "big bang" replacement of all existing telephony infrastructure.

Mobile Apps and Softphone Clients

A UC platform is only as good as its client applications. For hybrid work, the mobile app and desktop softphone client determine whether remote employees have an equivalent experience to those in the office.

Microsoft Teams Mobile App

The Teams mobile app (iOS and Android) provides full Teams functionality on smartphones: calls, video, chat, and file access. For Bangladesh employees working from home or travelling, the Teams app on a smartphone with sufficient data connectivity provides complete UC functionality.

For voice calls specifically, the Teams app uses your internet connection (Wi-Fi or cellular data) to carry VoIP calls. With Grameenphone 4G/5G coverage in Bangladesh's major urban areas, Teams call quality on mobile is generally good — comparable to a WhatsApp voice call but integrated into the business UC environment.

Teams Desktop Client

The Teams desktop client (Windows, Mac) is the primary UC interface for office-based and home-office workers. It supports all Teams features including video conferencing with background blur, device selection (choose between headset, laptop speakers, desk speakerphone), and meeting room join functionality.

Physical IP Desk Phones

Despite the shift to softphones, physical IP desk phones remain important for some use cases:

Reception desks where a physical phone is more practical than a headset
Executive offices where desk phone etiquette is culturally expected
Call centre agent positions where a headset connected to a physical phone is ergonomically preferred

Teams-certified IP phones from Yealink (T55A, T58A), Poly (Edge E Series), and Fanvil display the Teams interface natively, with the familiar Teams icon and meeting join flow. These phones register directly with Microsoft Teams Phone System — no separate IP PBX required for these endpoints.

Bangladesh Hybrid Work Context Post-2020

Bangladesh's experience with hybrid work has been different from Western markets in important ways. The pandemic period forced remote work capability that many organisations had not previously considered necessary. The aftermath has not produced the same sustained work-from-home adoption as in North America and Europe — Bangladesh's office culture, housing constraints (apartments that are not conducive to home offices), power reliability concerns, and management preferences have meant that most Bangladesh enterprises have returned primarily to office-based work.

However, certain hybrid work patterns have become permanent:

Senior management mobility: C-level and senior executives continue to use Teams for meetings that would previously have required physical attendance in Dhaka
Multi-site coordination: Organisations with multiple offices use Teams to reduce inter-city travel
Client and vendor communication: Video conferencing with international clients and suppliers is now standard, replacing much of the international travel that was routine before 2020
Emergency resilience: Having UC capability means that work can continue during disruptions — flooding, hartals, power outages (if UPS and mobile data are available)

These patterns mean that every Bangladesh enterprise benefits from a robust UC infrastructure, even if it does not use the platform for daily full-remote work.

Network Requirements for UC Platform Performance

Deploying a UC platform without the network to support it results in choppy video, dropped calls, and a user experience that undermines adoption. The network requirements for Teams-based UC are specific and must be planned:

Bandwidth

Microsoft's recommended bandwidth for Teams per user session:

1:1 HD video call: 1.5 Mbps up/down
Group meetings with video enabled: 4.0 Mbps up/down
Background blur and AI effects: additional 1.5 Mbps

For a 200-person Bangladesh office with 30 simultaneous video meetings during peak collaboration hours: 30 × 4 Mbps = 120 Mbps of internet bandwidth in each direction. This is readily achievable with enterprise fiber from GP Enterprise, Robi, or BTCL (100–1,000 Mbps symmetrical available in Dhaka's major business districts).

QoS for Teams

Microsoft publishes specific DSCP marking recommendations for Teams traffic — media packets should be marked EF (DSCP 46), signalling packets DSCP 26 (CS3). Network switches, routers, and the internet-facing firewall must be configured to honour these markings and prioritise Teams media traffic over general data traffic.

Network Segmentation

Teams media traffic should be on the same VLAN as other voice traffic, separate from general data VLANs, to facilitate consistent QoS treatment and to simplify security policy application.

Wi-Fi Design for UC

Wi-Fi performance for Teams calls requires careful access point placement, channel planning, and 802.11r/802.11k fast roaming configuration — so that a user walking from one end of the office to the other during a Teams call does not experience a call drop as they transition between access points. Wi-Fi 6 access points, properly planned and configured, are the current recommendation for UC-heavy office environments.

Building Your UC Strategy

A UC strategy is not just a technology decision — it is an operational and cultural shift in how your organisation communicates and collaborates. The technology platform (Teams, or an alternative) is the enabler. The real work is change management: helping employees understand the platform, adopt its capabilities, and change the habits (WhatsApp groups, desk phone calls, email chains) that the UC platform is designed to replace.

SSAL's unified communications practice covers the full scope:

UC platform assessment and architecture design
IP PBX and SIP trunk integration for Teams Direct Routing
Network readiness assessment and QoS configuration
Video conferencing room hardware design and installation
IP phone deployment for Teams-certified endpoints
Training and adoption support for IT administrators and end users

Talk to Our Expert — Contact SSAL to discuss your UC strategy and implementation roadmap. We help Bangladesh enterprises move from fragmented communication tools to a coherent, productive unified communications environment that supports how your team actually works.