Expense Control Function of the PBXs

Every time a telephone call is made, money is being spent. Many of the PBX functions help an organization to control this expense.

Toll Restriction

Toll restriction enables you to program the telephone system so that each extension has what is called a class of service. Each class of service designation enables the extension to call certain areas and restricts it from calling others. The most sophisticated systems can be programmed to restrict the dialing of specific telephone numbers. Others can restrict by area code or by area code and exchange. Figure 1 shows a typical scenario.



Internal Calls Only



Local Calls Only to 212, 646 and 917



Local Calls to 212, 646, 917, 718, and 914



Local and Long Distance Calls Within NY Metropolitan Area 212, 646, 917, 718, 914, 203, 860, 516, 972, 908 and 201



Local and Long Distance Calls to Continental US



Local and Long Distance Calls to US and Canada Only



Unrestricted - Can Call Anywhere in US or International

Figure 1: Classes of Service for Toll Restriction (Example)

You may also use class of service to give each extension access to certain system functions and restrict it from using others.

You may hear the term six digit toll restriction, meaning that the first six digits dialed (the area code and exchange) can be restricted through programming. Ten digit toll restriction enables you to restrict dialing to a specific telephone number.

Automatic Route Selection

Most PBXs and some key systems have the capability for ARS (Automatic Route Selection)or LCR (Least Cost Routing), which are essentially the same thing. Many larger telephone systems have separate outside lines that, when used, will result in a lower cost for certain telephone calls. For example, your company may have a direct line (dedicated line) connecting you to a long distance carrier. When a call has been dialed from your telephone system, the ARS recognizes where the call is going and sends it over the lowest cost route, based upon how the system has been programmed.

In the 1960's, '70's and '80's many companies had WATS lines (Wide Area Telephone Service). WATS lines were separate outside lines enabling calls to be placed at a discounted rate to specific geographic areas within the U.S. (Band 0 through Band 5, as the areas were called.) It was during this period that the ARS was most important. Now the decisions are simpler.

Telephone systems without ARS can get around this by assigning access codes to separate groups of outside lines called trunk groups. In this scenario, you may dial 9 for local calls and dial 8 for long distance calls to access a separate group of lines.

Call Accounting

Most telephone systems also have the capability to provide information on the calls being made through the system. This includes the time the call was placed, the duration of the call and the telephone number dialed. This is called SMDR (Station Message Detail Recording) output, Call Accounting output, CDR (Call Detail Recording) output, or AIOD (Automatic Identification of Outward Dialing), an out-of-date term seldom used. It's important to understand that the PBX provides the raw data only. In order to do anything with the data, it must be captured and processed into a usable format.

In many organizations, the SMDR output is stored in a buffer device that then is polled by a call accounting system, usually on site. Call Accounting is usually PC-based. It accepts the call information from the PBX. It then assigns a cost to each call that approximates the true cost of the call and sorts the calls by extension number. The costs for each extension may also be grouped into department reports, often provided to each department manager.

Calls may also be sorted by account codes, numbers associated with certain clients or projects of the company. Thus, a law firm will know how much is being spent on each client and may use the information for billing call charges back to the client. Under these circumstances, the PBX requires the dialing of an account code before each outgoing call is made. The PBX keeps the account code associated with the call and sends this information to the buffer device.

Traffic Study

Most PBXs provide information on how the outside lines in the system are being used (call volume on each outside line). This is called a traffic study. Although the call accounting system is capable of providing a traffic study, it is not always set up to do so. Instead, the telephone installation and maintenance company is customarily called upon to poll the PBX for a period of time, often a week, to provide the traffic information. When requesting a traffic study, it is important to be very specific about the information you want and what your objective is.

You may have had a new telephone system installed with 20 outside lines for which you are paying $30 each per month (20 x $30. = $600). Now it's a year later and you want to find out if you really need all of those lines.

A traffic study runs for one week and tracks all incoming and outgoing calls. The results indicate that at the busiest times of the day, no more than 10 of the lines are ever in use. Being conservative, you decide to leave 15 lines in place and remove the other 5 (5 x $30 = $150), thus saving your company $150 per month.


When you remove outside lines, remind your telephone installation and maintenance company to reduce your maintenance cost, since it is often based upon the number of ports used for outside lines. You must also have your telephone system re-programmed so that it will not be looking for the missing lines when someone dials 9 or, in the case of your DID trunks, when a call comes in.

Here's another situation for which you may wish to run a traffic study. Callers to your organization complain that they are reaching a busy signal. The one-week traffic study shows that all 20 outside lines are in use ten percent of the time, confirming that during this time callers cannot reach your company. You order 5 more local outside lines from the local telephone company and have them connected to your system by the telephone installation company. You may need to buy an additional circuit board for the system to accommodate these new lines. Several weeks later you run another traffic study that shows that at the busiest times of day, no more than 22 lines are in use. Callers cease to complain about busy signals.

The traffic study also measures call volume on T-1 circuits.

It's a good idea to have a traffic study run on your telephone system at least once a year. You may negotiate an annual traffic study as a part of your PBX maintenance contract. Or you may learn how to run the traffic study in-house with your call accounting system.

MAC (Moves and Changes)

Many companies spend thousands of dollars moving telephones around the office and changing the extensions or features on the telephone. This activity is MAC work (MAC = moves and changes). It can be provided by your telephone installation company. Most PBXs enable you to do some of your own MAC work using a PC with software that makes program changes to the PBX. In some older systems, the changes may be done with a keyboard only or a dumb terminal.

For example, two executives are exchanging offices. It is necessary to change the extensions appearing on the telephones in each of the offices, on the secretaries' telephones, and on the telephones of the groups backing up each of the secretaries. If the telephones are all in place, these changes may all be done from the on-site MAC terminal, without calling in the telephone installation company. It is always advisable to inspect the individual telephones to be sure that the changes took effect and to change the paper labels which most telephones still use. (Note: Some newer systems enable users to take the telephone with them and plug it in in the new office, retaining all of the extensions and features.)

Another example of a PBX change which can be made on-site is that of changing the toll restriction on a telephone. Your call accounting system may indicate that a lot of long distance calls are being made from the lunchroom telephone. Since employees are permitted to make local calls only, that telephone is now reprogrammed so that only calls to the local exchange can be made. All other call attempts will be routed to the switchboard attendant.

An advantage of having a MAC terminal on site (and someone in your company trained to use it) is that it will provide you with current information about how your system is programmed. Otherwise, you may be dependent on your telephone installation company or may even need to collect the information manually. MAC terminals may enable you to obtain the following:

  • A list of all extensions in use in your telephone system.

  • A list of all spare (unused) extensions in your telephone system.

  • A list of all outside lines (trunks) in your telephone system. This will be by the trunk number assigned to each outside line in the PBX. It will not provide the actual telephone number assigned to the line by the local telephone company, although there may be a field for this to be manually entered.

  • A company telephone directory listing name, department and extension number.

  • A list of all extensions with their associated class of service, meaning which areas can be called and which system functions can be accessed.

  • A list of all classes of service in use in the system and what they mean.

  • A list of how each extension is programmed to forward calls under a variety of conditions, including when the extension is busy and when it is not answered.

  • Information on how each of the slots and ports is used in the PBX control cabinet.

  • Identification of spare slots and ports available for expansion.

No comments:

Telecom Made Simple

Related Posts with Thumbnails