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Introduction to Westbay Traffic Calculators
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Click here to find out how to purchase
The programme consists of a single window, with tabs to select between
the Erlang C Calculator, the Call Minutes Calculator, Erlang B Calculator and the Extended
Erlang B Calculator. The latest version boasts many new features including support for
C.C.S. and Extended Erlang B. It has a progress bar to show you the progress of a
calculation. The package also has the ability to display and print the results of any
calculations you have made during the previous week.
Westbay Traffic Calculators now includes Erlang for Excel free of charge. This is a Add-In for
Microsoft Excel version 97 or higher which allows call center calculations to be included
in your own spreadsheets.
The calculators, which require Microsoft Windows 95, 98,
ME, NT4, 2000 or XP, are available for 139 US Dollars. Click here to find out how to purchase. |
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Erlang C Calculator (Call center)
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| The Erlang C Calculator can be used for calculations
involving the queuing of telephone calls. This means that it offers a way of calculating
the number of call centre agents or switchboard operators required if the call volumes are
known. The calculator works up to one million calls per hour and 10,000 agents! 
"What percentage of calls will be answered within 20
seconds if my call centre receives 650 calls in an hour of average duration 150 seconds
and my call centre is manned with 34 available agents?" Answer - 94%
The Erlang C Calculator simplifies the complicated calculations required
to predict and analyse call centre performance. There are a number of variables involved
in such calculations including the number of calls received per hour, the average duration
of the calls and the required answering performance.
The calculator can be used to answer such questions as:
- How many agents does a call centre need?
- How many calls can the operators handle?
- What duration of calls can be handled?
- What will the average delay to incoming calls be?
- How many calls will be answered within target?
You can view the fully
illustrated User Guide now to find out more about how the calculator works and see how
these questions are answered.
Technical specification available.
Why not try an online
version of this calculator to see how it works (requires JavaScript). |
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| The Call Minutes Calculator is used to work out how many
lines a trunk group requires if the number of minutes of traffic offered to that trunk
group in one day are known. Reverse calculations are also supported which allow you to
estimate how many minutes of traffic a trunk group can be offered per day. The
calculator works up to 30,000,000 million call minutes per day! 
"How many lines does a trunk group need? It is offered
50000 minutes of traffic per day and I accept that 3% of calls will be blocked. I estimate
that 19% of daily calls are made during the busiest hour?" Answer - 168
Reverse calculations are also possible to help you work out how many
minutes of calls a trunk group can be offered. More information is available in the fully illustrated User Guide.
Technical specification available.
Why not try an online
version of this calculator to see how it works. |
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| The Erlang B Calculator is based on the Erlang B traffic
model and is used to work out how many lines are required on a trunk group if the traffic
and the required grade of service are known. Traffic values can be entered in either
Erlangs or C.C.S. (Centi-call seconds). The calculator works up to 25,000 Erlangs
/ Lines! 
"How many lines do I need in a trunk group if that
trunk group is offered 200 Erlangs of traffic during its busy hour and I accept that 1% of
calls will fail due to blocking?" Answer - 221
Unlike similar products, you can also carry out these calculations in
reverse. For example, you can find out what the probability of blocking would be for a
given busy hour traffic figure and trunk group size. If you know two of the variables, you
can work out the third. You can view the fully
illustrated User Guide now to find out more about how the calculator works and study
example calculations.
Technical specification available.
Why not try an online
version of this calculator to see how it works. |
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Extended Erlang B Calculator
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| The Extended Erlang B Calculator is very similar to the
Erlang B calculator but also takes into account the additional traffic created by callers
immediately trying to redial a number if their call is blocked. This calculator produces
slightly more accurate results if no overflow facilities are available on a trunk group.
As with the Erlang B calculator, reverse calculations may be carried out and the
calculator works up to 25,000 Erlangs / Lines! 
"How many lines does a trunk group require if it is
offered 200 Erlangs of traffic during its busy hour and I accept that 5% of calls will
fail due to blocking, half of which are immediately retried?" Answer - 207
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| The Westbay Traffic Calculators are provided with a fully formatted and
illustrated User Guide which is distributed electronically in the form of Web pages. This
User Guide explains how to use the calculators and offers many examples of their use.
There is also a Windows help system which is installed with the software. You can view the fully illustrated
User Guide now to find out more about how the calculator works and study example
calculations.
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Purchasing
Westbay Traffic Calculators
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The Westbay Traffic Calculators, which comprises the three calculators
described above, cost 139 US Dollars for a single user
licence. You can pay using any major credit card.
Transactions are with Westbay Engineers Ltd. (our parent company) and
are handled on the secure server of WorldPay, our e-commerce
supplier. You can have the software running on your PC five minutes from now!
(In exceptional circumstances, online payments can take up to one
working day to complete)
Our price list is fixed in US Dollars. During the ordering
process, you will be able to change this to the equivalent amount in Euros or Pounds
Sterling. American Express and Diners Club transactions are only available in Pounds
Sterling - the equivalent rate will automatically be presented to you before you purchase. |
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Please choose a licence type
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| Please take a moment to consider the type of licence you require. Your honesty
in this matter helps us to continue developing our products. Software piracy is
illegal. |
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| Alternatively, if you would prefer to pay by cheque or
money wire, please contact us. |
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| Try looking in the FAQ (Frequently Asked Questions). Someone else may already have asked
the same question. Failing that, please send us an
email. |
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Erlang B / Ext. Erlang B |
Erlang C |
Call Minutes |
| Operating system |
Windows 95,
98, ME, NT4, 2000 or XP. |
| Traffic model used |
Erlang B / Ext. Erlang B |
Erlang C |
Erlang B |
| Operational limits |
BHT 25000 (max) Erlangs
Blocking 0.001 - 0.500
Lines 25000 (max)
Retries 95% (max) |
ACD Agents 1 - 10000
Calls per hour 1000000 (max)
Duration 10000 (max) seconds |
1 - 30000000 mins. per day
Blocking 0.001 - 0.500
Lines 25000 (max) |
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