An on-premise IP PBX is a phone system that runs on a hardware appliance or server physically located at your office, which you own outright. A cloud (hosted) PBX runs on the provider's servers and you pay a monthly per-seat fee. On-prem means a larger one-time spend but full control of your data and configuration; cloud means lower upfront cost and no hardware to maintain. The right choice depends on your priorities around control, connectivity and budget.

Anywhere from around 16 extensions on a small appliance to several thousand on enterprise-grade servers, often expanded with licence packs and additional modules. The key is to size for where you'll be in two years so you add capacity with a licence rather than replacing hardware. The comparison tool lets you filter by extension count.

Yes. Modern IP PBX systems connect to Indian carriers over SIP trunks, and PRI or analog (FXO) lines are bridged in using gateways — so your existing numbers and copper lines keep working alongside IP. We confirm trunk and line compatibility for your specific carrier before you buy.

One of the main reasons businesses choose on-prem: internal extension-to-extension calling continues on your local network regardless of the internet, and if you have PRI or analog lines, calls to and from the PSTN keep working too. Only SIP-trunk calls that rely on the internet are affected — which is why many sites keep a PRI line as backup.

Because the hardware lives with you, plan for an annual maintenance contract (AMC) with a local partner for updates, spares and support, plus a UPS and basic power protection to keep the system up. We match you with installers who offer AMC and can advise on the right redundancy for your site. Voice usage still follows TRAI norms — this is general guidance, not legal advice.