London-based telecommunications test and measurement specialist DSPG Ltd, has launched a new low-cost telephone network emulation test package, providing a wide range of functions in a compact solution. The DSPGenie Telephone Network Emulator (TNE) surpasses the functionality of existing, high-cost test equipment, and should fulfil a much-needed role in the testing of high-speed voiceband data modems and fax terminals, where performance can be critically dependent on the quality of the network connection.

 

It provides network operators and equipment manufacturers with a cost-effective testing platform starting at the most basic system with a single add-on PC card implementation of the 2-wire/4-wire Central Office function, digital signal processing power, and software to configure gains and impairments. The arrival of the DSPGenie TNE underlines DSPG's continuing leadership in the development of high performance telecommunications test solutions, under the banner of its DSPGenie family of products.


The low-cost DSPGenie TNE is designed as an easy-to-use instrument that is capable of introducing all the main impairments that adversely affect voiceband data communications. Impairments of various types, introduced by a poor quality connection, can lead to digital transmission errors and consequent increased transmission time due to the need for re-transmission of corrupted data. Developers of such data communication devices therefore need realistic network emulation to test their designs effectively, and network operators need the same network emulation capability to evaluate the products of different manufacturers.

In addition to its prime function, the DSPGenie TNE can be used to connect any 2-wire telephone instruments (standard or calibrated). This allows the DSPGenie TNE to be used for subjective evaluation purposes, either of the telephone instruments themselves, or of some aspect of the emulated connection. Typical parameters and impairments controlled by the DSPGenie TNE are send and receive gains, echo levels, noise levels, delay, and local loop characteristics. All impairments can be introduced independently in the two directions of transmission, and the instrument can also measure and display signal levels.

Additionally, there are options to include various low bit-rate codecs in the connection, as well as the ability to introduce external equipment via a primary-rate PCM interface. To accommodate these facilities, it is generally necessary to use the fully self-contained instrument version of the DSPGenie TNE. Housed in a mini portable 3U case, this compact unit contains an in-built single-board computer, and there is an option to have a touch-sensitive display screen on the front panel. The touch-screen allows user-friendly selection of all the necessary emulation parameters, dispensing with the need for a keyboard, mouse and monitor to be permanently connected to the unit. It is used to control the DSPGenie TNE in a similar way to mouse-control in a Windows-based environment.

It is also possible to operate the portable unit from an external host computer via a built-in Ethernet interface, using readily available commercial software packages.

Specific features of the DSPGenie TNE tester are implemented by on-board Field Programmable Gate Arrays (FPGAs). Under PC control, the application programs are downloaded into the DSP memories and the system configuration files are downloaded into the FPGAs. A fully upgradeable solution, future changes to either the tester's firmware or software only require software upgrades on the PC.