When interfacing to the E1 line with Secondary Over Voltage protecTIon or in a high return loss configuraTIon, resistors are added between the DS2153 outputs and the transformer. Normally the resistors are of different values depending on whether the interface is driving a 75Ω coax or 120Ω twisted wire pair line. Also a change in the termination resistor is required. A single set of resistors can be utilized in both situations by using the circuit shown in Figure 1. The dotted lines indicate jumper positions for selecting 75Ω or 120Ω operation.
![DS2153, DS2154 Selectable 120,第2张 DS2153, DS2154 Selectable 120,Figure 1. E1 interface.,第2张](/upload/website_attach/20220726/2009420103012287.gif)
Figure 1. E1 interface.
Table 1. Line Interface Control Register Settings
Notes:
- Transformers shown are available from Pulse.
- Resistors shown are within 1" of best value.
欢迎分享,转载请注明来源:内存溢出
评论列表(0条)