By the SightShield team · · 3 min read
Still need desk phones?
Many offices now run on mobile phones and video calls, but reception, internal extensions, conference rooms, factories and front desks still need a shared phone system. The old EPABX box in the server room is being replaced by IP-PBX systems and cloud telephony, which handle extensions, call routing and intercom over the office network and on staff phones.
Three options compared
| Option | How it works | Best for |
|---|---|---|
| Analog or digital EPABX | A box with phone lines and wired extensions | Small offices and factories with existing wiring |
| On-premise IP-PBX | A server or appliance in the office; IP phones on the network | Mid-size offices wanting control and no per-user fees |
| Cloud telephony | Provider hosts the system; phones and apps connect over the internet | Multi-branch, hybrid teams, quick setup |
Features that matter
- Extensions for every desk, cabin and meeting room.
- Reception console showing who is busy, with call transfer.
- Auto-attendant: “Press 1 for sales, 2 for support”.
- Ring groups and hunt groups for teams.
- Softphone apps so staff answer office calls on mobiles or laptops.
- Call recording and reports where legally and ethically appropriate, with notice.
Door and gate intercom integration
IP-PBX and many cloud systems can treat a SIP video door station as an extension. A visitor presses the button at the office door or factory gate, reception’s phone rings with video on screen, and a key on the phone releases the door. This removes a separate intercom system and works from any extension.
IP intercom vs analog intercom →Cabling, PoE and power
- IP desk phones use a network point and are powered by PoE, so no adapters at each desk.
- Many phones have a pass-through port for the desk computer, saving cable runs.
- Put the IP-PBX, switches and router on a UPS so phones work during power cuts.
- Use a separate VLAN for voice to keep call quality steady.
Internet quality and regulation
Cloud and SIP calling depend on a stable internet connection with low jitter; offices relying on them should consider a second internet line. In India, connecting internet calling with regular phone lines is governed by telecom regulations and licensed providers, so use licensed telephony providers and follow their guidance on numbers, call routing and record keeping.
Business internet and dual-ISP failover →Choosing by office type
| Office | Usual choice |
|---|---|
| 10–20 people, mostly on mobiles | Cloud telephony with a few desk phones and softphones |
| 30–150 people, one site | On-premise IP-PBX or cloud, with PoE desk phones |
| Factory with shop-floor phones | IP-PBX with rugged or analog phones through adapters |
| Multi-branch business | Cloud telephony with extensions across branches |
An example
A 70-person office in Koramangala replaced a 15-year-old EPABX with an on-premise IP-PBX and PoE desk phones on a voice VLAN. The reception desk got a console, sales and support got hunt groups, and staff installed softphones for working from home. A SIP video door station at the office entrance rings reception’s phone and releases the door. The old two-wire cabling was retired as desks moved to network points.
Choosing the right system
We assess your call patterns, cabling and branches and recommend EPABX, IP-PBX or cloud telephony, then install phones, network and door integration together.
Intercom and phone systems →Quick answers
What is the difference between EPABX and IP-PBX?+
An EPABX uses phone lines and wired extensions; an IP-PBX runs calls over the office network with IP phones and apps.
Is cloud telephony better than an IP-PBX?+
It suits multi-branch and hybrid teams with no hardware to maintain; an IP-PBX gives more control and no per-user fees.
Can office phones open the door?+
Yes, a SIP door station can ring extensions and be released from the phone.
Do IP phones work in a power cut?+
Yes, if the PoE switch, PBX and router are on a UPS.
Can I keep my existing office numbers?+
Usually yes. Your telephony provider can advise on moving numbers to a new system within the regulations.
Can staff answer office calls on mobiles?+
Yes, through softphone apps on IP-PBX and cloud systems.