Nortel Networks 9150 - Manual (Page 44)

14 Remote Gateway 9150 Installation and Administration Guide
Remote Gateway 9150 description Standard 3.1
64K (56K) dynamic adaptation
With some carriers, 64K calls routed over a 56K PSTN infrastructure may cause
errors. The dynamic adaptation feature allows the Remote Gateway 9150 unit
and the RLC to dynamically detect the limitation of the bandwidth. The call is
then downgraded from 64K to 56K.
Bandwidth allocation
The RLC automatically allocates trunk bandwidth to the Remote Gateway 9150
connection as needed. For example, as calls are initiated and bandwidth
requirements increase, additional trunk connections are established. Likewise, as
calls terminate and bandwidth requirements drop, connections to idle trunks are
terminated.
Connection types
The Remote Gateway 9150 connection to the RLC can be defined on the RLC as
permanent or on demand. A permanent connection means that the ISDN
connection to the host PBX always remains open. An on demand connection
means that the ISDN connection is established only when a connection with the
host PBX is required.
If the connection is defined as demand, then you can configure minimum call
duration and idle timers on the RLC to help reduce call charges.
Minimum call duration timer
Most ISDN tariffs specify minimum charges incurred when you open the line,
regardless of the call duration. This charge is the minimum call charge listed on
long distance telephone bills.
The minimum call duration timer is used in PSTN mode only and specifies the
minimum length of time that each PSTN call to the host PBX remains active,
regardless of telephone activity or inactivity. Configure the timer on the RLC to
drop inactive connections just before an additional charge period is incurred. For
example, if the timer is set to 59 seconds and your call lasts only 20 seconds, the
ISDN connection drops when the timer reaches 59 seconds.