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In the present era, digital transmission of data plays a vital role in every sector. The main aim of this paper is to design a cost effective device which can test a transmission data and find the errors if any at the receiving end. Products based on this concept, having customizable options are widely available but with high cost. Most of the options in the testing equipment are unused, so there has been a requirement of a customized IP based tester with V.35 and PCM E1 framer which can serve in testing MODEMS. The 32 bit microcontroller STM32 monitors all the blocks on the testing board. The peripherals are connected to STM32 using various interfaces. The pattern generated is modulated on the transmission side of E1 framer or V.35. The MODEM receives the pattern and loops back it to the receiver section of E1 framer or V.35. Here the pattern is recovered via demodulator and passed to the BERT (Bit Error Rate Tester). If both are same then there will be no Bit Error, otherwise status register and bit error register values get updated automatically indicating the possibility of the error. The number of patterns generated by BERT is 23 and can be connected with multiple modems to test their working corresponding to different patterns. This process ensures the communication between MODEMS and BERT in a safest mode. Keywords-Bit Error Rate, Microcontroller, E1 Framer, BERT, Modem.

-When the length of the filter and consequently the number of filter coefficients increase, the design of the filter becomes complex and therefore the popular NLMS algorithm has been replaced with MMax NLMS algorithm. But its performance in terms of convergence characteristics reduces to an extent though the filter design becomes very easy i.e., convergence occurs at a later stage taking too much computational time for the processing of the signal. In this paper, a proposal for improving the convergence characteristics is made without compromising the performance of the design and affecting the tap-selection process of the MMax NLMS algorithm. With the introduction of the concept of variable step-size for the filter coefficients, loss in the performance due to MMax NLMS algorithm can be effectively lowered and the convergence is better achieved in the filter deign.