Connecting Calculator blocks

By connecting calculators together, you define the order in which the calculations take place. For example, you could start with an Extended Erlang B Calculator block to estimate how many lines you need, and then connect this to a Voice over IP Calculator block to convert this into a bandwidth figure for transmission through an IP based network.

To connect two calculators, you must first switch the programme into Add connection mode in one of the following ways:

•	Select Blocks \| Connect from the main menu.

•	Right click in the workspace where the Calculator blocks are placed, and select Connect blocks.

•	Each toolbar has a Connect blocks button. Press the button.

Once in Add connection mode, the cursor will change to a cross when it is moved over the workspace. To connect two Calculator blocks, move the cursor over the first block, press and hold down the left mouse button, and drag the mouse to the edge of a second block. As you move the mouse, you should see a line appearing from the first block. When the cursor is over the second block, release the mouse button.

Connection rules

Not all Calculator blocks can be interconnected. For a pair of Calculator blocks to be connected, the output type of one Calculator block must match the input type of the next Calculator block. The example, the output of the Erlang B [BHT >> Lines] block is a number of lines. This can be connected to the Lines to IP Bandwidth block, because the input of that block is also a number of lines.

Details of all the Calculator blocks available are given in this help system. Press the Contents button at the top of this window, and select the Calculator block from the Calculator blocks option.

The direction of the link is important; it defines which Calculator block will be executed first. The arrow shows the direction of the calculation.

Adding corners

Connections are not limited to single straight lines. It can be more convenient to add corners to the connections. To add a corner, select the link using the left mouse button, and then click the left mouse button while the cursor is over the point where the corner is to be added. The corner can then be moved by dragging it with the mouse.