AL2094S Designers Guide
Doc. No. DG_2094E
Altec Electronic AG
Seite 13 / 30
2.7 Telephony
Extensions
The following telephony extension features are supported and can be typically be
implemented in designs for set-top box applications and TAM software applications to
enhance end-user experience:
•
Line In Use detection
•
Extension Pickup detection
•
Remote Hang-up detection
2.7.1 Line In Use Detection
The Line In Use Detection feature can stop the modem from disturbing the phone line when
the line is already being used. When an automated system tries to dial using ATDT and the
phone line is in use, the modem will not go off hook and will respond with the message “LINE
IN USE”.
2.7.2 Extension
Pickup Detection
The Extension Pickup Detection feature (also commonly referred as PPD or Parallel phone
detection) allows the modem to detect when another telephony device (i.e., fax machine,
phone, satellite/cable box) is attempting to use the phone line. This feature can be used to
quickly drop a modem connection in the event when a user picks up a extension phone line.
For example, this feature allows set top boxes with an integrated SmartV.XX modem to give
normal voice users the highest priority over the telephone line. This feature can also be used
in Telephone Answering Machine applications (TAM). Its main use would be to stop the TAM
operation when a phone is picked up.
2.7.3 Remote Hangup Detection
The Remote Hangup Detection feature will cause the modem go back onhook during a data
connection when the remote modem is disconnected for abnormal termination reasons
(remote phone line unplugged, remote server/modem shutdown. For Voice applications, this
method can be used in addition to silence detection to determine when a remote caller has
hung up to terminate a voice recording.
2.8 Caller
ID
Both Type I Caller ID (On-Hook Caller ID) and Type II Caller ID (Call Waiting Caller ID) are
supported for U.S. and many other countries (see Section 2.11). Both types of Caller ID are
enabled/disabled using the +VCID command. Call Waiting Tone detection must be enabled
using the +PCW command to detect and decode Call Waiting Caller ID.
When enabled, caller ID information (date, time, caller code, and name) can be passed to
the DTE in formatted or unformatted form. Inquiry support allows the current caller ID mode
and mode capabilities of the modem to be retrieved from the modem. Type II Caller ID (Call
Waiting Caller ID) detection operates only during data mode in V.90, V.34, V.32bis, or V.32.
2.9 Worldwide
Country
Support
Internal modem firmware supports 29 country profiles (see Section 1.3.2). These country
profiles include the following country-dependent parameters:
•
Dial tone detection levels and frequency ranges.
•
DTMF dialing parameters: Transmit output level, DTMF signal duration, and DTMF
interdigit interval.
•
Pulse dialing parameters: Make/break times, set/clear times, and dial codes are
programmable
•
Ring detection frequency range.
•
Type I and Type II Caller ID are supported for many countries. Consult firmware release
notes for a list of the supported countries and the criteria for additional country support.
•
Blind dialing enabled/disable.
•
Carrier transmit level (through S91 for data and S92 for fax). The maximum, minimum,
and default values can be defined to match specific country and DAA requirements.
