AN301| Application Note
Maxim/Dallas > App Notes > COMMUNICATIONS CIRCUITS Keywords: T1, E1, T1/E1, 8MHz, backplane, PCM, pulse code modulation, elastic store, DS0, 2.048MHz, system clock, framer, byte interleaved, IBO, interleave bus operation, SCTs, single chip transceiver, stream
May 29, 2001
APPLICATION NOTE 301
Legacy T1/E1 8MHz Backplane Operation
Abstract: This application note provides the requirements for multiplexing four PCM streams into one 8MHz system backplane using Dallas Semiconductor/Maxim SCTs and framers that do not contain interleave bus operation (IBO) modes internally.The DS2155, DS26528, DS26524, DS26522, DS26521, DS26519 and DS26518 all contain IBO functionality without external circuitry and are recommended for new designs.
Introduction
This application note applies to the following products: T1 Framers E1 Framers T1 SCTs E1 SCTs DS2141A DS21Q41B DS2143 DS21Q43A DS2151 DS2153 DS2152 DS2154
This application note will discuss the requirements for multiplexing four PCM streams into one 8MHz system backplane using Dallas Semiconductor SCTs and framers that do not contain interleave bus operation (IBO) functionality internally. > The DS2155, DS26528, DS26524, DS26522, DS26521, DS26519 and DS26518 all contain IBO functionality internally and do not need the extra logic shown below. T1 or E1 PCM signals can interface to an 8MHz system backplane. Typically, this application is used to multiplex four PCM streams onto a single 8MHz PCM stream. To accomplish this, the elastic stores are enabled and placed in the 2.048MHz SYSCLK mode. Figure 1 illustrates a circuit in which a single SYNC signal is generated for all four framers. Each framer in turn is driven with an 8.192MHz clock burst of 8 cycles. Each clock burst causes the elastic store to output one DS0. This results in a byte-interleaved 8.192MHz PCM steam (see Figure 2). Figures 1 and 2 apply to the DS2152 and DS2154. Figure 1 shows the 8.192MHz cl
ock can optionally be derived from a master DS2152/54.
AN301 Application Note maxim Download PDF
Add this permalink to your bookmarks for future download of AN301 ApplicationNote
Permalink: http://application.emcelettronica.com/maxim/AN301
