Customer Premises Equipment (CPE) Customer Premises Equipment (CPE) CPE is defined as any telephone terminal equipment which resides at the customer’s site and is connected to the Public Switched Telephone Network (PSTN). Telephones, modems, caller ID adjunct boxes, PBXs, and answering machines are all considered CPE. Protection Requirements The following regulatory requirements apply: • TIA-968-A (formerly known as FCC Part 68) • UL 60950 All CPE intended for connection to the PSTN must be registered in compliance with TIA-968-A. Also, because the National Electric Code mandates that equipment intended for connection to the telephone network be listed for that purpose, consideration should be given to certifying equipment with an approved safety lab such as Underwriters Laboratories. CPE Reference Circuits Figure 3.1 through Figure 3.6 show examples of interface circuits which meet all applicable regulatory requirements for CPE. The P3100SB and P3100EB are used in these circuits because the peak off-state voltage (VDRM) is greater than the potential of a Type B ringer superimposed on a POTS (plain old telephone service) battery. 150 VRMS √2 + 56.6 VPK = 268.8 VPK Note that the circuits shown in Figure 3.1 through Figure 3.6 provide an operational solution for TIA-968-A (formerly known as FCC Part 68). However TIA-968-A allows CPE designs to pass non-operationally as well. For a non-operational solution, coordinate the IPP rating of the SIDACtor device and the I2t rating of the fuse so that (1) both will withstand the Type B surge, and (2) during the Type A surge, the fuse will open. (See Table 5.1, Surge Rating Correlation to Fuse Rating on page 5-8.) Note: For alternative line interface protection circuits, see "Regulatory Compliant Solutions" on page 4-34. © 2004 Littelfuse, Inc. SIDACtor® Data Book and Design Guide 3-3 http://www.littelfuse.com +1 972-580-7777 Reference Designs CPE should be protected against overvoltages that can exceed 800 V and against surge currents up to 100 A. In Figure 3.1 through Figure 3.6, SIDACtor devices were chosen because their associated peak pulse current (IPP) rating is sufficient to withstand the lightning immunity test of TIA-968-A (formerly known as FCC Part 68) without the additional use of series line impedance. Likewise, the fuse shown in Figure 3.1 through Figure 3.6 was chosen because the amps2time (I2t) rating is sufficient to withstand the lightning immunity tests of TIA-968-A without opening, but low enough to pass UL power cross conditions. Customer Premises Equipment (CPE) 0461 1.25 Tip P3100SB or P3100EB To Protected Components Ring Figure 3.1 Basic CPE Interface Transmit / Receive 0461 1.25 + Tip - P3100SB or P3100EB Ring + Ring Detect Figure 3.2 Transformer Coupled Tip and Ring Interface 0461 1.25 Tip P3100SB or P3100EB Relay Transmit/ Receive Circuitry Ring Ring Detect Figure 3.3 Modem Interface http://www.littelfuse.com +1 972-580-7777 3-4 © 2004 Littelfuse, Inc. SIDACtor® Data Book and Design Guide Customer Premises Equipment (CPE) Transistor Network Interface Hook Switch 0461 1.25 Tip Ring Ringer Dialer IC DTMF Speech Network Handset Figure 3.4 CPE Transistor Network Interface — Option 1 Transistor Network Interface Hook Switch 0461 1.25 Tip Ring Ringer Option 2 P1800SB or P1800EB Dialer IC DTMF Speech Network Handset Figure 3.5 CPE Transistor Network Interface — Option 2 © 2004 Littelfuse, Inc. SIDACtor® Data Book and Design Guide 3-5 http://www.littelfuse.com +1 972-580-7777 Reference Designs Option 1 P3100SB or P3100EB Customer Premises Equipment (CPE) 0461 1.25 Tip Transistor Network Interface P3100SB or P3100EB Ring Ring Detect Note: Different Ground References Shown. 0461 1.25 Tip Transistor Network Interface P3100SB or P3100EB Ring Ring Detect Figure 3.6 Two-line CPE Interface http://www.littelfuse.com +1 972-580-7777 3-6 © 2004 Littelfuse, Inc. SIDACtor® Data Book and Design Guide