Calculating The Number Of Rlt Circuits - Nortel TFC002 Manual

Page 28 of 64 Engineering information

Calculating the number of RLT circuits

553-2681-100 Standard 5.00
To calculate the number of RLT circuits required between a particular
Remote site and the Main site, the following grades of service must be
specified. Tables 3 through
Average speed of answer
This is the average time in seconds that a call from the Remote site, which
requires an attendant, waits at the Main site for an attendant to answer.
Average RLT delay
This is the average time in seconds that a call from the Remote site, which
requires an attendant, waits at the Remote site for an RLT to become idle
under average busy season busy hour (ABSBH) traffic.
Note 1: Where ground-start signaling is used for RLT circuits (for
example, with a QPC250 RLT trunk card at the Remote site and a QPC70
CO trunk card at the Main site), add a minimum of 2.5 seconds to the
average RLT delay. There is a minimum average delay of 2.5 seconds
from the time that the RLT is seized at the Remote site until the time that
it is interpreted as an incoming call at the Main site.
Note 2: The RLT 20 percent overload delay is fixed at 10.0 seconds
and is reflected in the values shown in
The calculation of the number of RLT circuits required between a Remote site
and the Main site requires the following information:
— The number of calls per hour in the Remote site that require an attendant.
— The attendant work time (AWT). This is the average time in seconds
taken by an attendant at the Main site to service a call.
August 1996
20 calculate the RLT requirements.
Tables 3 through 20.