Interfacing to the Fractional
IntroducTIonThis application note shows a "looped-timed" application where a Dallas framer or single-chip transceiver (SCT) is configured for a fractional T1 / E1 interface.
This application note applies to the following products:
| T1 Framers | E1 Framers | T1 SCTS | E1 SCTS | T1 / E1 SCTS |
| DS2141 | DS2143 | DS2151 | DS2153 | DS2156 |
| DS21Q41 | DS21Q43 | DS2152 | DS2154 | DS2155 |
| DS21Q42 | DS21Q44 | DS21352 | DS21354 | DS21Q55 |
| DS21FF42 | DS21FF44 | DS21552 | DS21554 | DS21455 |
| DS21FT42 | DS21FT44 | DS21Q552 | DS21Q554 | DS21458 |
| DS21Q352 | DS21Q354 | DS36528 | ||
| DS26524 | ||||
| DS26522 | ||||
| DS26521 | ||||
| DS26519 | ||||
| DS26518 |
General ConfigurationIt is common for a T1 / E1 carrier subscriber to not have the full T1 / E1 rate of service, but a fractional T1 or E1 service, since the full bandwidth may not be needed or affordable. The circuit shown in Figure 1 shows an example of a fractional T1 / E1 circuit design, where the application is "looped-timed" and connected to a V.35 / RS-449 / S530 interface. In this figure, the transmit and receive FT1 / E1 streams occupy the same time slots. The DS2175 is our T1 / CEPT Elastic Store IC and the XR-T8000 is the Exar Clock Synchronizer / Adaptor for Communications IC. The idle registers on the Dallas framer / SCT can be used to fill unused channels, and the used channels do not need to be contiguous. RCHBLK can be used with TCHBLK to allow up to three additional FT1 / E1 ports. Reset should be activated after all the clocks are stable.
Figure 1. Fractional T1 / E1 to V.35 interface.
ConclusionThis application note has shown how to design our framers / SCTs for fractional T1 / E1 in a "loop-timed" application.
If you have further questions about fractional T1 / E1, please contact the Telecommunication Applications support team via email var name = "telecom.support @"; var domain = "dalsemi.com"; document.write ("" + name + domain + ""); telecom. or call 972-371-6555.
Dallas Framer / SCT InformationFor more information about our framers / SCTs, please consult the data sheets available on our website at
The JUK universal Screw Terminal Block series has the typical features which are decisive for practical applications:
l The universal foot allows the terminal blocks to be easily snapped onto the NS35 or NS32 DIN Rail with G shape.
l Closed screw guide holes ensure screwdriver operation perfect.
l For terminal block with different wire cross-sectional areas, complete accessories are available, such as end plates, partition plates, etc.
l Potential distribution achieved by fixed bridges in the terminal center or insertion bridges in the clamping space.
l Same shape and pitch Grounding Terminal Blocks as the JUK universal series.
l Adopt ZB marker strip system,achieve unified identification.
Screw Terminal Block Types,Beige Screw Terminal Block,Good Quality Terminal Block,Screw Terminal Blocks
Wonke Electric CO.,Ltd. , https://www.wkdq-electric.com