subject: Telephone Management - Options For Data Acquisition [print this page] A Telephone Management system uses CDR or call data records as produced by the PBX as its most fundamental input. Without data input a telephone management system is useless. Collecting data is a specialist skill, its importance is often overlooked and not given the attention it deserves.Each call data record CDR has a real value as it contributes to the accuracy of the Telephone Management system as a whole. If call records are lost the accuracy of reports suffers as a consequence.A PBX outputs CDRs by one of three methods, IP data, Serial data and as a file. Each format must be handled very differently.Via SerialNormally produced from a serial RS232 port and shares the limitations of serial data. The specification of RS232 limits the cable length between the sender and receiver to 15 meters. In reality this can be much further, and can often work up to distances of 50 meters. However for reliable transfer of CDR we should attempt to stay within the publish specifications.IP data:Within this category there are two methods. The first, a PBX may produce call records and simply drop them onto the network in addressed packets. This method has no service guarantees at all. Taking this method to the extreme, it is possible to transport addressed packets over the Internet however, with valuable data, this is unreliably and not recommended. Even data transported over an Intranet in this manner may suffer from packet loss and therefore the Telephone Management system useless. The second method uses hand shaking between the devices creating a reliable data collection channel.Via a FileThe PBX writes CDR to a file in a shared directory, where the Telephone Management system can access the information.By definition, serial and IP data need additional equipment to ensure reliable collection of CDR. Several companies offer a solution for this in the shape of a Call Buffer. A call buffer device, normally located technologically close to the PBX receives the CDRs, stores and forwards them safely to the Telephone Management application.Types of call bufferSerial data in - Serial data out. The device receives call records at a particular baud rate store the data until the host application is ready to receive it, then forwards it a baud rate suitable to the host.Serial data in - IP data out. We use this device to receive serial and change it to IP for transmission over a local area network.Send CDR over the Internet: A device that collects either serial or IP data and delivers it via secure protocols to the web based telephone management service. The data delivery method may be FTP, HTTP, and even SMTP mail. These methods can be made secure and reliable by messaging between the Call Buffer and the host Telephone Management system.Data collection devices come in the form of either a solid state ultra reliable purpose built box, or can be a software program running on a PC within the client environment.The price of Data Collection Devices varies wildly between suppliers with a high of around US$500 and a low of US$200.
Telephone Management - Options For Data Acquisition
