SMDR Call Accounting

call accounting

SMDR, or Station Messaging Detail Record, is the data sent by a PBX, or PABX, about a telephone call to a computer or other device for storage and reporting. This information is usually accessed via call accounting software.


SMDR data has information such as:

  • The date and time of the call
  • The duration of the call
  • The telephone extension involved
  • The trunk line involved
  • The direction of the call, inbound or outbound
  • The manner in which the call was completed, for example ring out
  • The number dialed - for outbound calls
  • Caller id - for inbound calls, this is the phone number that called the PBX
  • DDI - for inbound calls, this is the phone number that was dialed
  • Account code - an indication that the call was involved with a specific project
  • Authorization code - used to gain access to telephone line or class of service, for example long distance
  • Ring time - the duration the phone rang before being answered

There may be multiple SMDR records associated with a single telephone call as the call is transferred from one extension to another or is handled by an auto-attendant. A single SMDR record may be represented by one or more lines of text. Simple SMDR records may look like the following:

2018-06-24 20:14:40 03:38 I 00:05 100 07
2018-06-24 20:15:02 04:35 O       109 06 5551157
2018-06-24 20:16:10 03:56 I 00:01 103 07
2018-06-24 20:16:19 01:09 I 00:01 102 05
2018-06-24 20:16:42 03:13 O       105 04 5557821

Call Accounting

The SMDR port on a PBX may be connected to a computer running call accounting software. As each record is received by the call accounting software is it stored in a database for later reporting.

Call accounting reports may be a simple chronological list of calls, detail reports of call traffic about specific telephone extensions or trunk lines, total reports over periods, graphical or other variations.

Simple call accounting applications may run as a program requiring a user to be logged on to a computer. More appropriate applications might run as a program or service in the background. Both these types of applications must maintain database performance by running regular indexing and optimization automatically or by a user. Database backups must also be maintained by users.

Newer call accounting applications are available as software-as-a-service, or as cloud computing applications. In these applications the only software that runs at the customers' location is a small data collection program that sends SMDR call records to a remote data center and reports can be run from a standard web browser.

A cloud based SMDR call accounting program might look like this one.

Copyright © TIM IP Pty Limited 2011-2018