POTS & DSL Phone Lines

DSL and POTS Tip & Ring Ports Metallic Connection

Design Notes:

Protection Application:
This note covers three examples of POTS (Plain Old Telephone Service) Tip & Ring Port protection where there is no ground reference. This is often called a “metallic" connection. Metallic applications are usually associated with the CPE end of the line. POTS lines carry normal voice telephone signals. During ringing, the voltages can approach 275 volts. These solutions can also be used for most DSL applications.
Solution Description:
Littelfuse offers a range of POTS SIDACtor®, GDT and TeleLink or PTC solutions. Some common solutions are presented in the diagrams at the left. Any of the OVP solutions can be used with any of the OCP solutions. Selection will be based on cost and the level of protection desired. The P3002SB and SL0902A series solutions are best for DSL lines.
Companion Solutions:
A SL1002 GDT is also available. The P3100EB is a TO-92 thru-hole option. GDTs can be surface mount or thru-hole. Customers have used the 230 Series 1.25 Amp 2AG fuse as well.
Regulatory Issues:
These solutions are designed to comply with: TIA-968-A, UL60950 & EN60950 & YD/T 950-1998 ITU K.21 & YD/T 993-1998
Unique Features:
The P3002SB solution is unique to Littelfuse.
Application Warnings:



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