SMDR Software for Call Accounting

SMDR software receives information about telephone calls from your PBX (or PABX) and can be used to discover information about your telephone system and ultimately reduce your business expenses.

SMDR information can indicate if you have too many or too few telephone lines, if you are missing calls before or after regular business hours or if an inappropriate number, duration or destination of calls are being made.

As telephone calls are completed your PBX sends information about your calls to the PBX SMDR (or CDR) port. The SMDR port on your PABX can be connected to a computer and information sent from your PBX can be received by SMDR software for recording, analysis and reporting.<

SMDR reports are often available in both text and graphic format. Some SMDR software permits you to export data in CSV format, some software may allow you to automatically receive reports as PDF via email.


Before SMDR information can be read by an application the SMDR port of the PBX must be connected to a computer (or other device). PBXs often offer connectivity via serial or IP connection.

If using a serial port the cable length between the PBX and computer is limited and the correct serial port settings such as baud rate and parity must be configured.

If connecting the PBX to the computer via IP (network cable) the PBX does not have to be in close proximity to the computer. Depending on the PBX either the PBX or computer acts as a server (waiting for a connection) and the other device acts as a client (and connects to the server).

CDR and SMDR records

Each CDR (Call Detail Record) also known as SMDR (Station Messaging Detail Record) contains information (metadata) about the call such as; the extension on which the call occurred; the duration of the call and the telephone number dialed.

Each PBX manufacturer usually uses a different PBX information format. SMDR call record information may be recorded as a single line of text per call, two or more lines of information or even a page of information detailing the call.

Simple, single line SMDR call accounting records may look something like the following:

Sq Date       Time  Dur.  Ext Tr Dialed
60 2021-09-19 16:35 00:02 101 01 O95551234
61 2021-09-19 16:45 00:15 103 02 I
62 2021-09-19 16:48 00:23 106 09 I
63 2021-09-19 16:49 00:07 101 01 O95551235
Time  Dur.  Ext Dialed
16:35 00:02 101 O95551234
16:45 00:15 103 I
16:48 00:23 106 I
16:49 00:07 101 O95551235

Different PBXs may have different settings to turn different parts of the SMDR information on or off. Some PBXs may not display incoming calls at all, if they do they won't unless your telephone provider supplies caller ID. Some SMDR formats include information about why the call was terminated, others provide information about the DDI number called.

An often over looked configuration item is the date format, the same date format must be used by both the SMDR and the call accounting application that reads the data. If date formats are not the same, for example one is day-month-year and the other is month-day-year, call records are stored for the wrong date or unable to be stored due to invalid dates.

A simple solution?

Over the years many different SMDR software providers have created many different call accounting solutions. Some systems have been designed from the ground up to be a commercial product, others have started life 'in-house' to provide a SMDR call accounting solution to handle calls for their own business.

As SMDR software solutions are created developers discover that writing SMDR software starts as a very simple exercise. Extracting call duration, start time and phone number can be a simple exercise for a simple PBX type. But as other call accounting features such as multi-part and abandoned calls and other PBXs are supported by the SMDR call accounting software developers discover that the processing of calls is not the simple exercise they originally thought them to be.

As SMDR software is put into use users often discover that a lot of calls are quickly recorded by the software. A simple SMDR call accounting software solution records each call in a database (as it should) without any thought to how the calls will be used. To keep costs low an inexpensive or free database solution is often used and as the number of SMDR records in the database increases the performance of the SMDR software can rapidly decline.

A typical 'solution' to SMDR call accounting software becoming slow is to delete SMDR records from the software database. This may seem like a solution but it prevents long-term and historic reports and comparison reports being run.

After a short while cheap solutions provide more problems:

  • as the number of records increase reporting and even time to log in increases
  • some reports take so long to run the user guides may recommend to NOT use some reports
  • to 'fix' slow reports the user guide says to delete 'old' records
  • using a cheap or free database there are few or no database tools
  • daily backups are required to be performed by you
  • when you need the SMDR software you discover the system hasn't been operating

Some call accounting solutions bill themselves as 'state-of-the-art' or 'industrial strength' but in reality are legacy applications. Such applications brag about a database of 'one million records'; 'under development since 1998' and look like they've not been updated in 10 years; some advise you 'not to use this report'.

If the call accounting provider's public message, their website, has not been updated in years or has a copyright date from years ago how much attention are they really paying to their product?

Business expenses

When purchasing an SMDR software solution a cheap solution might seem like an easy fix to a quick-and-dirty requirement. Remember the adage 'you get what you pay for'. Many SMDR software applications although billed as industrial strength, ultimate or up-to-date when installed may look like a school project. If the user interface has a 'school project' look about it the core of the solution is likely to be the same.

One of the prime features of SMDR software is to discover the cost of the outgoing telephone calls. However, some call accounting solutions have this turned off by default. If call costing is supported often the bare minimum requirements are supported.

If a SMDR software solution is being used to calculate call cost (after all that is one of the primary reasons for installing SMDR call accounting software) a number of reports can be used to discover costly call areas and reduce business expenses.

Typical call cost discovery and recovery reports include:

  • trunk utilization or all trunks busy report to determine unused telephone lines thereby reducing monthly rental or to discover that the number of telephone lines provided by your supplier is insufficient to handle your customer enquiries
  • recharge call costs to customers or other departments
  • top calls by cost to discover calls to expensive numbers
  • top calls by number dialed to discover frequently dialed numbers to suppliers, customers or non-business calls
  • calls to expensive services such as mobile, international or premium numbers
  • internal time wasting calls where staff are unnecessarily chatting
  • discovering a high number of abandoned calls outside business hours might indicate poor customer service or missed business
  • discovering toll fraud where your telephone system is being used by others

Ongoing development and support

After SMDR software has been released often that is the last work the developer may perform on the application. Bugs may not be fixed and as newer PBX features and call costing options become available the SMDR call accounting software may become out of date.

Ask when the software was last updated, how often the SMDR software is updated. Why is the version number or copyright message on the application or website supporting the software out of date. Perhaps a one off purchase of a legacy SMDR software call accounting solution is not the best buy, perhaps a monthly rental of an online solution is better.

Real call accounting solutions

An online, hosted SMDR call accounting solution provides the call accounting features you want without you having to keep asking your software provider for software updates. Hosted call accounting solutions have all the core SMDR software hosted online and as the online solution is updated you use the latest software. No more software updates to download and install.

Perhaps the largest and unnoticed feature of a hosted SMDR software solution is that all the parts of a SMDR software product that usually fails and require maintenance is the SMDR database. Remember the 'too many records and running slow fix' of deleting records? A hosted solution does not have to do that. Instead of using cheap or free database systems to keep costs down a real database solution is used with the costs spread over many customers. No longer do you have to learn how to support, maintain and backup a database, now that is all done for you.

A cloud call accounting solution provides up-to-date SMDR call accounting software without you needing to learn how to decode, support and maintain SMDR information and become a database administrator.