Avaya Media Gateway G250, Administration Manual

Page: 138 / 840

Configuring Standard Local Survivability (SLS)
138 Administration for the Avaya G250 and Avaya G350 Media Gateways
Note:
Note:
DID is a method of routing calls that applies to both analog and digital (T1/E1)
lines. However, while the method is typically referred to as DID in the analog
world, it is usually called Dialed Number Identification Service (DNIS) in the digital
world. Despite the difference in names, the concept is the same.
The gateways support DID central office trunk interfaces, and the digit transmission from the
central office is configurable when ordering the service:
●
Immediate . The DID signaling starts immediately after the central office seizes the analog
DID trunk by closing the loop (across tip and ring). In addition, analog DID trunk lines only
support inbound calls. For this reason, Customer Premise Equipment (CPE) utilizing DID
trunk lines for inbound routing may utilize loop-start lines for outbound transmission.
●
Wink . The DID signaling starts after the gateway’s analog trunk interface reverses the
battery polarity and sends a “wink” to the central office.
!
WARNING:
WARNING:
An analog two-wire DID trunk line is different from a standard analog loop-start
line. With analog DID trunk lines, the battery (power feed) to the line is supplied
by the gateway’s analog trunk interface. With a standard loop-start line, the power
is supplied by the central office, which is why damage can occur from connecting
a loop-start PSTN trunk to the DID port.
The number of sent digits (3-4 typically) and signaling type (Pulse/DTMF) are also configurable
at ordering time.
Multiple call appearances in SLS mode
When a gateway is in SLS mode, three call appearances, each with limitations, are supported:
●
The first two call appearances are for incoming or outgoing calls. The first call appearance
is the default.
●
The third call appearance is for outgoing calls only.
Note:
Note:
“First", "second", and "third", refer to the order in which you use call appearances,
not the order of the Call Appearance buttons on your phone.
For example, User A chooses the third call appearance to dial User B, and then User C calls
User A, which is sent to the first call appearance. In this situation, a subsequent inbound call to
User A will be denied (busy) because the first and third call appearances are in use, and the
second call appearance is only available for outbound calls.