Who is that Calling?

By David M. Parker, CompetitiveNetworkSolutions.com




7703 Fairway Vista Court

Cordova, TN  38016



Ring, Ring, now I see the Caller ID display and it says Unknown Caller.  Chances are, it’s a business calling you from their PBX (Private Branch Exchange).  If you’re screening calls from telemarketers, you may or may not choose to answer the phone, however, it might be your friend.  You just don’t know. 


There are several different types of telephone lines or trunks that are used for various purposes.  The most common is the Line, that most all of us use at home.  Unless you subscribe to an additional service, when you call someone with a Caller ID display unit, they know its you, and its up to them to answer it or not.  Businesses don’t use lines, since they typically have a higher volume of phone calls.  Introducing, the Ground start trunk.  The GS trunk is very similar to a line, and is installed by the Telephone Company in a similar fashion to your Line service, and yes, features are available.  The benefit to small businesses is that the GS trunk is less-likely to experience collision, where an inbound and outbound call simultaneously arrive at the serving local central office.  Expecting to hear dial tone, someone is already there.


As technology progressed, true trunk service was derived from 4 wires, using E&M signaling (ear and mouth).  This type of trunk virtually eliminates the collision of calls, and is widely used by businesses today.  Remember the Unknown Caller on your display?  Yep, that’s who’s calling, someone behind a PBX using E&M trunks.  Is there a workaround?  Technically yes, but it is very expensive.  I researched adding this “feature” to a client’s E&M trunk service and the carrier told me (after three weeks of research) that they’d have to purchase additional software from their vendor to provide it.  Hold on!  This should not be that difficult!  In reality, for carriers, it is.  So what’s next?


ISDN (Integrated Services Digital Network), fondly referred to as I Still Don’t Know, solves the trunk problem of sending out originating telephone number information, and opens up the door to several interesting features that can work with business telephone systems.  In a basic installation, ISDN trunks send the Billing Telephone Number (company’s main number) on their outbound calls so your Caller ID unit will display the number.  Take it a step further, and the ISDN user can enable a feature to allow the actual extension of the person calling you to be sent.  Example: If my main number is 555-444-3000, and my company has a block of numbers ranging from 3000 to 3100, I can enable the service to send each and every number in the range, depending upon who called.  If my extension was 3150, and I called a Caller ID user, they’d see 555-444-3150 on their display. 


It is possible to see who’s calling, but it depends on what kind of service they’re calling from, and what additional services they may have ordered from the telephone company.  Private Caller is just one of those features.



This series of articles is posted at:  http://www.competitivenetworksolutions.com/


© Copyright: Competitive Network Solutions, Inc. 2001. All rights reserved.


Bio: David Parker, President of Competitive Network Solutions, Inc. has spent over 19 years in the Telecommunications field, at companies such as MCI Telecommunications, MCI WorldCom, and Comsat General.  Recently, he formed Competitive Network Solutions, Inc. as a consulting firm, specializing in Business Continuity Planning and Telecommunications consulting.  He is a resident of the Memphis area, and has traveled internationally in support of his professional endeavors.  He has also spoken in large customer forums in several Southeastern and Mid-Atlantic cities on Business Continuity Planning and is a member of the Memphis Area Business Continuity Planning committee.  Competitive Network Solutions is a member of the Memphis Area Chamber.