Dallas transceivers connect four T1, E1, J1 lines

Dallas Semiconductor has disclosed that its DS21455 and DS21458 4-port devices are the only available transceivers that do not require external component changes to switch among T1, E1, and J1 standards.

The products contain all the line interface and framer functions necessary to connect four T1, E1, or J1 lines. According to Dallas, no relays or switched external components are required, and that a single clock supports all standard T1, E1, or J1 operating modes. All ports are independently configurable and can be interleaved on the same 16.384MHz backplane. Additional transceiver

features include software-selectable receive and transmit termination, two HDLC controllers per port, programmable bit-error-rate testing (BERT) and optional crystal-less jitter attenuation.

The DS21455 is pin and software compatible with the DS21Q55 for convenient migration of existing designs, while the DS21458 is software compatible with the DS21Q55. The DS21455 is packaged in a 27-by-27mm CSBGA, whereas the DS21458 has a slightly smaller package of 17-by-17mm.

All transceivers are available in commercial and industrial temperature ranges. Prices start at $36.99 for the DS21458 and $39.99 for the DS21455. An evaluation kit is also available to help speed designs.