Fxs Voice Subscriber Line; Fxs Interface; Fxo Voice Subscriber Line; Fxo Interface - 3Com MSR 50 Series Configuration Manual

2246 C 131: V
HAPTER OICE
FXS Voice Subscriber
Line

FXS Interface

FXO Voice Subscriber
Line

FXO Interface

S L C
UBSCRIBER INE ONFIGURATION
Signal tones support two modes: country mode and custom mode. In addition,
the amplitude of signal tones can be customized for the avoidance of signal tone
detection failure in special cases.
A foreign exchange station (FXS) interface uses a standard RJ-11 connector and a
telephone line to connect to an ordinary telephone, or fax machine. The FXS
interface accomplishes signaling exchange based on the level changes on the
Tip/Ring line to provide ringing, voltage, and dial tone.
CID The caller identity delivery (CID) service means that the calling identity information
such as calling number, date, and time is displayed on the called terminal.
With the CID function, calling numbers and calling time in single-data-message
format can be transmitted or received in an on-hook state. When the CID function
is combined with services such as call forwarding - unconditional (CFU) and call
forwarding - busy (CFB), calling identity information can also be transmitted if
required. A message in the single-data-message format contains the following
information:
Date and time when a voice call occurs (MM DD hh:mm).
■
Calling number if CID is enabled on the device
■
P" if CID is disabled on the device.
■
"O" if the terminating PBX fails to obtain the calling number (e.g., the
■
originating PBX end does not send it)
The FXS voice subscriber line sends the calling number to the called telephone.
The calling number is sent to the called telephone between first and second
ringing through frequency shift keying (FSK) modulation. Therefore, the called
user must picks up the telephone after the second ringing to ensure that the
calling number is sent and received correctly. Otherwise, the calling number may
fail to be displayed.
A foreign exchange office (FXO) interface, namely, two-port loop trunk interface,
uses a standard RJ-11 connector and a telephone line to connect a local call to a
public switched telephone network (PSTN) or PBX. Like an FXS interface, an FXO
interface accomplishes signaling exchange based on the level changes on the
Tip/Ring line. An FXO interface can be connected only to an FXS interface.
CID The FXO voice subscriber line receives the calling number from the PBX. The FXO
interface receives the modulation information of the calling number from the PBX
between the first and second ringing. The calling number then undergoes FSK
demodulation and parity check. The function of sending calling number is checked
for its enabling status after the parity check succeeds. If the function is enabled,