
Calling Party Supervision
The U.S. telephone network typically uses Calling Party Supervision, meaning
that even though the called party hangs up, she/he may be reconnected to the
calling party when the phone is taken off-hook again. The calling party must hang
up for the called party to be fully disconnected before initiating a new call. The
telephone network will timeout and disconnect the call within 5-20 seconds,
giving the called party dial tone when she/he goes off-hook again. Outgoing
Calls from the SLSS
The SLSS allows touchtone and rotary dialing on outgoing calls.
Outgoing Telephone Calls– SLSS Idle
When a telephone connected to the SLSS goes off-hook, it switches to the Central
Office line for dial tone. When the phone goes back on-hook, the line returns to
an idle condition. (When the line is idle, it is connected to a local battery feed.)
Outgoing Telephone Calls– SLSS Active
If in Total Priority Mode, while the modem is active, a priority port going
off-hook remains connected to the local battery feed while the SLSS disengages
the active port.
-or-
If in Emergency Priority Mode, the telephone at Port 1 receives dial tone
(generated internally by the SLSS). Dialed digits are monitored. If the dialed
phone number does not match the programmed emergency numbers, busy tone
is sent to the telephone user. If, however, the dialed number matches a
programmed emergency phone number, the line is freed for the telephone user.
The SLSS then dials the number and connects to the Central Office line. The caller
must enter the emergency number within 30 seconds or the SLSS goes into Privacy
Timeout. (This ensures that calls will be routed even if the Port 1 telephone is
off-hook indefinitely. See page 30 for more detail about Privacy Timeout.) In this
mode, Port 2 has priority over Ports 3 through 8.
If you have programmed an Access Code, Port 1 will get access to the line
whenever the access code is entered, even if the number dialed is not a
programmed emergency number.
-or-
If in No Priority Mode, the modem or other device remains active and the line is
not assigned to another port.
Incoming Calls to the SLSS
When the SLSS is idle, the incoming Central Office line is disconnected from the
internal phone line. The SLSS answers all calls at the end of the first ring period.
It then monitors for a routing code.
Reference Manual
Chapter 6: Standalone SLSS Operation and Features
40-400-00031, Rev. A
Page 39