Specifications

Features

 1. Single supply voltage: +3.3V to +5.0V

 2. Integral high efficiency DC/DC converter

 3. Transformerless 2-wire to 4-wire conversion

 4. Integral ringing generator

 5. Constant current feed

 6. Tip/Ring Polarity reversal

 7. On-hook transmission

 8.Off-hook detection

 9. Easy to use, with a minimum number of external components.

 10. Simplified protection in “on-premise” applications.

 Applications

1. Voice Over Internet Protocol (VoIP)

2. Cable Modems

3. Key Telephone System

4. IP Gateway system

5. Wireless Desktop Phone

6. Set-top Box System

7. Voice Over DSL (VoDSL)

8. Short Loop Access Platforms

9. Remote Subscriber Units

10. Other Terminal Adapters

Functional Description

1. Switch Hook Detection

When the subscriber goes “off-hook” loop current will begin to flow. If this current is above the detection threshold the switch hook output, SHK, will switch to a logic (H). It is recommended that software or hardware de-bouncing of the switch hook signal is used. This is to avoid shot pulses which can cause a false switvh hool output, triggering the incorrect system response.

During loop disconnect dialing, SHK will pulse between logic (H) and logic (L) to indicate the digits being dialed. Again it is recommended that software de-bouncing of the pulse edges is used to avoid false detection of digits.

1. Tip & Ring Polarity

The QCX601 can reverse the battery voltage polarity at Tip and Ring via the RFL pin. RC and 25HZ is at logic (L).

If RFL is held at logic (H) (Forward) the d.c. voltage at Ring is negative with respect to Tip. If RFL is taken to logic (L) (Reverse) the voltage at Ring is positive with respect to Tip.