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Maxim > Design Support > Technical Documents > Application Notes > T/E Carrier and Packetized > APP 356
Keywords: E1, framer, software, hardware, differences, register, compatible, replace, framer devices
APPLICATION NOTE 356
DS21Q44 vs. DS21Q43A
Mar 29, 2001
Abstract: This application note describes the hardware and software differences between the Dallas
Semiconductor DS21Q44 and the DS21Q43A quad port framer devices. The DS21Q44 quad E1 framer,
offers a broader feature set while retaining the original features of the DS21Q43A. As such, the designer
must decide on what changes need to be made in software and hardware when migrating to the
DS21Q44 from the DS21Q43A quad E1 framer. Any designer who is thinking of upgrading an existing
design to use the DS21Q44 should read this application note. The application note contains detailed
information for software migration such as: register location changes, how individual functions have
changed from the DS21Q43A to the DS21Q44, and which new functions are available on the DS21Q44.
It also covers migration for the hardware interface and covers new functions that are available in the
DS21Q44. In the end, the designer should have enough information to easily migrate an existing design
which uses the DS21Q43A to the DS21Q44 device.
Overview
This application note highlights the differences between the DS21Q44 and the DS21Q43A Quad E1
framers. The DS21Q44 is a superset of the DS21Q43A. The DS21Q44 is offered in a 3.3V version with
5V tolerant I/O. All of the original features of the DS21Q43A (except the loss-of-receive clock status bit)
have been retained. Software created for the DS21Q43A is transferable to the DS21Q44 with minimal
effort.
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