RING SLIC for Signal QCX601

The QCX601 is designed for use short loop "on-premise" applications, such as FCT, FWT, WLL and VoIP. In this case power cross and lightning protection is not required. The only protection which should be required is for ESD (Electro Static Discharge) caused by handling during installation.
Features
Single supply voltage: +3.3V to +5.0V.
Integral high efficiency DC/DC converter.
Transformerless 2-wire to 4-wire conversion
Integral ringing generator
Constant current feed
Tip/Ring Polarity reversal
On-hook transmission
Off-hook detection
Easy to use, with a minimum number of external components.
Simplified protection in "on-premise" applications.
Applications
Voice Over Internet Protocol (VoIP)
Cable Modems
Key Telephone System
IP Gateway system
Wireless Desktop Phone
Set-top Box System
Voice Over DSL (VoDSL)
Short Loop Access Platforms
Remote Subscriber Units
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 short pulses which can cause a false switch hook output, triggering the incorrect system response.
During loop disconnect dialling, SHK will pulse between logic (H) and logic (L) to indicate the digits being dialled. Again it is recommended that software de-bouncing of the pulse edges is used to avoid false detection of digits
2. 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.