Postcards from the Centrex Edge

This blog entry was posted by Ed Margulies, Senior Director, Product Management CRM Service Products at Oracle. Margulies is a telecommunications architect, usability expert, inventor, and the author of 17 books on telecommunications, contact centers and service automation. The views expressed in this blog are Margulies' and do not necessarily reflect the views of Oracle.

Centrex: A CaaS Heritage

Centrex service is an excellent example of how CaaS-based offerings are successfully married to enterprise-based, on-premises applications. New York Telephone realized this 40 years ago. In the mid-sixties, this its customers asked for an alternative to the massive on-site switchboards of the day. New York Telephone's engineering department then added simple extension dial and transfer capabilities to their central office switches. These features allowed on-site phone extensions from the central office to act like an on-site switchboard system. And Centrex was born.

Early Centrex service came with large multi-button operator turrets and intermediary answering positions. Later, more sophisticated Automatic Call Distributor (ACD) applications such as the Pinnacle ACD option (AT&T 5ESS option) were developed. Even more heavy-duty uses of ACD SaaS offerings were co-mingled with special Emergency 911 software. The on-premises systems handle Public Safety Answering Point (PSAP) duty. Here the calling number ID passed by the Centrex system is used in conjunction with a computer-assisted dispatch (CAD) system. These CAD systems provide heads-up maps and other displays so the emergency dispatcher can use the map data to advise the best available responders.

Centrex meets on site Messaging Systems

Another Centrex-based innovation is the Simplified Message Desk Interface (SMDI). Here, the Centrex system sends information over a data channel dealing with line availability, phone call time stamps, forwarding information and the like. This is typically used to couple Centrex service with on-site SMDR (Station Message Detail Recording) call accounting software and on site Voice Messaging systems. The interface is emulated by numerous manufacturers now for interoperating between devices - even if they are not CaaS-based.

Enhanced Services based on Centrex later gave birth to Basic Rate ISDN offerings (now essentially replaced by cable and broadband DSL). The data channel on BRI lines enabled everything from simple file transfer to real-time third party call control for on-site PBXs and custom service center applications. In fact there were offshoots of this based on analog technology.

Centrex and the Birth of Short Message Service

Even Data over Voice technology has facilitated the marriage between CaaS and On-Premises Enterprise software. Data over voice is a way soup-up analog Centrex lines in lieu of the more expensive Basic Rate ISDN. Today this is the very popular Analog Display Service Interface (ADSI). It's also called CLASS (Custom Local Area Signaling Services). There are different versions of this service offering all over the world. It's quaint considering the data is sent on-hook using a simple Bell 202 1200 bit FSK modem circuit.

Now this technology is embedded in everything from Dialogic voice and network cards to televisions and modern single line phones. The applications for the technology are endless taking into account everything from simple Caller ID-based applications to "visual versions" of Interactive Voice Response - a.k.a. SMS and SMS-based services.

Centrex: Incubator for Spatial and Temporal Automation

As you can see, Centrex and associated services have been an incubator for a host of innovations - both in the temporal and spatial domains. On the temporal side, interfaces such as SMDI facilitate voice messaging and IVR (temporal) interfaces for automated services. On the spatial side, ADSI and SMS-type services transfer data visually as in a web site. In fact, you can look at new SMS-based services as kind of a visual version of IVR (Interactive Voice Response). Here the dialog is directed and not as self-directed and spatial as a web page.

The simplicity and convenience of SMS - that is the keypads on your cell phone - make it both ubiquitous and universal like the web. Traditionally, you text a friend or relative and get a simple chat-type dialog going. But now contemplate how an SMS can be sent from your phone to get automated responses from a machine. Companies like Agent511 offer automated applications like this (From your cell phone, text: DEMO to 511-511 for a sample).

So SMS is another medium pretty much dependent on CaaS. And the marriage between CaaS and the enterprise? OK, imagine how an SMS gateway can be used to route messages to an on-premises SMS-equipped ACD (Automatic Call Distributor). In this example, users can use published short codes to send SMS queries to a service center. Those messages are not answered by a single person, but are put into queue so the best-equipped agent can type back a response or push a URL to the "caller."

Companies like Oracle are developing this technology along with its customers and partners. The point is, you don't "own" an SMS even though you may own the telephone that you send it from. And on the other end, enterprise-based and software-controlled systems can respond to your text messages - all piggy-backing on the cell phone provider's SMS network - which in itself is a CaaS-based offering.

In summary, many innovations came out of the simple idea of Centrex. And today, modern CaaS services continue to add value to enterprise applications - just like Centrex has for almost half a century. Whether it's on-site messaging, Business Intelligence apps, contact center or SMS-based services, the co-mingling of CaaS and the enterprise seems pretty much here to stay.