Wireless & Other PBX Solutions

Wireless PBX Solutions

Several solutions for adding wireless extensions to PBX systems have been commercialized. Most PBX vendors have implemented proprietary 900 MHz-band solutions in the United States as well as the 1900 MHz Digital Enhanced Cordless Telecommunications (DECT) ETSI standard in Europe, which has driven widespread adoptions of vendor-neutral wireless there. More recently, a number of WiFi solutions have become available, as well as combination WiFi/GSM solutions that let a single device work with both Cellular and Enterprise PBX infrastructure. 

Other PBX Solutions

Two other PBX solutions with security considerations bear some discussion: Call Detail Recording (CDR) systems and Voice Firewalls. CDR systems enable every call on a PBX to be recorded after it is complete using a standardized format. This allows special reporting software to analyze this data for forensic or diagnostic purposes. It is worth noting, however, that a CDR system will not allow you to stop a fraudulent call still in progress. For this, you would need a voice firewall such as that sold by SecureLogix. Such a firewall allows you to see current calls in real-time, apply policy based on type of call (voice, fax, or data), and set notifications, authentication requirements, or other policy based on rules very similar to those you might set for data traffic on a data firewall.

All PBX systems provide PSTN-like switching services between endpoints and adjuncts, the PSTN, and other private PBX switches (and associated private networks). Only a few of the possible adjunct systems are mentioned here. An ACD is an Automatic Call Distribution server (for use in call centers to direct calls to groups of agents), and an IVR is an Interactive Voice Response server (also commonly used in call centers to let callers use touch tones and voice prompts to select services).

So a PBX could be all IP or all analog or anything in the middle as long as it switches calls between extensions and the PSTN as needed. In the end you will find that despite the marketing hype, most VoIP systems are just PBX systems with different combinations of support for IP lines and trunks. In some cases, the call control part of the system is split out from the gateway that handles the non-IP electrical interfaces. Or it’s pushed out to a service provider. But the basic switching concept is preserved somewhere across the system as a whole. Regardless, understanding basic PBX terminology will help you understand the underlying architecture of the VoIP systems you may encounter, so let’s start there.