IP PBX Telephone Exchange Systems

The PBX is the one box that decides where a call goes. Phones register to it over the network, outside lines arrive on SIP trunks or analog ports, and everything else — extensions, groups, voicemail, recording, paging — is configured inside it.

• SIP desk phones, hotel handsets and intercom terminals register as extensions over the LAN
• Analog phones and fax machines connect to FXS ports where the model has them
• Outside lines arrive as SIP trunks over the internet, or as analog lines on FXO ports
• Recording, voicemail and voice prompts live on the internal storage, or on a recording server

Extension numbers start at 200 by default, and analog line dialling delay defaults to 1000 on the smaller models and 600 on the larger ones.

Two numbers decide it: how many SIP trunks you need, and how many analog ports. Everything else follows.

• No analog ports at all, pure SIP, and you need redundancy — OM1000-UC
• Dozens of analog ports with room to grow in the chassis — OM200G
• Up to 48 analog ports in a rack, AC or DC — OM80E
• Keeping six to twelve analog lines in a desktop box — OM50G
• A small office, and cellular backup matters — OM20G

The feature set is common across the range. The differences between models are capacity, ports, power and redundancy.

• Auto attendant with time-of-day routing, up to three periods per day, and multi-level IVR
• Operator position with up to five numbers, ring groups with sequential, rotating or simultaneous distribution, and queues of up to 20 waiting calls
• Call transfer in six variants, hold, park, pickup, three-way calling and call waiting
• Do-not-disturb, hotline, abbreviated dialling groups, call barring by time and day, and five outbound permission levels
• Voicemail retrieval by dialling *98, with the option to forward messages to a mailbox
• Wake-up calls, call recording, satisfaction surveys and alarm notification
• Security: access white list, static and dynamic defence, login lockout, TLS and SRTP options, and SIP signalling and voice-payload encryption
• Management: web GUI or SSH, auto provisioning over DHCP option 66, TR069, and call detail records pushed to an external server