AN273 Datasheet, PDF (1/8 Pages) Silicon Laboratories – GR-909 TESTING WITH THE Si321X PROSLIC®

AN273
GR-909 TESTING WITH THE Si321X PROSLIC^®
1. Introduction
This document describes how line fault testing (such as GR-909) may be implemented using the Si321X family of
ProSLIC devices. Demonstration code for each test is available.
2. GR-909 Metallic Loop Tests
The five metallic loop tests described by GR-909 are as follows:
1. Hazardous Potential Test
Under any condition, the following must be detected
>50 V_RMS ac voltage from TIP-GND or RING-GND
>135 V dc voltage from TIP-GND or RING-GND
2. Foreign Voltage Test
Under any condition, the following voltages not generated by the SLIC must be detected
>10 V_RMS ac from TIP-GND or RING-GND
>6 V dc from TIP-GND or RING-GND
3. Resistive Faults Test
Detect the following resistive line faults
<150 kΩ TIP-RING, TIP-GND, or RING-GND
4. Receiver Off-hook Test
Distinguish between resistive fault <150 kΩ and an off-hook receiver
5. Ringing Equivalency Number Test
Determine the REN (Ringer Equivalency Number) of the terminating receiver is between 0.175 REN and
5 REN. Reject if outside that range.
Each of these tests can be implemented on the Si321x devices. Table 1 enumerates the test cases, the measure-
ment method implemented, and the failing criteria.
Table 1. GR-909 Metallic Loop Tests
GR-909 Test
1
Test Description
Hazardous Potential
2
Foreign Voltage
3
Resistive Faults
4
Offhook
5
REN
Linefeed State
OPEN
OPEN
TIP-OPEN, RING-OPEN
TIP-OPEN
RINGING
Measurement
V_TIP and V_RING
V_TIP and V_RING
R_TG, R_RG, R_TR
R_TR
PQ2
Failure Criteria
> 50 Vrms ac
> 135 V dc
> 10 Vrms ac
> 6 V dc
>150 kΩ
Detect/No-detect
> 5 REN
Rev. 0.1 2/06
Copyright © 2006 by Silicon Laboratories
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