There are three kinds of patch panel:

Use an octopus cable to connect a port of a POTS card to the first type of the patch panel.

The second type is more popular than the third so in most cases you can't plug an RJ11 plug into an RJ45 socket of your patch panel. Connecting an RJ11 plug into an RJ45 socket of a non-compatible patch panel can cause a defective contact.

The third type can accept RJ11 plugs without issues.

Besides, an RJ45 socket can be used to connect up to 4 pots phones. In this case, an adapter cable must be used to connect a POTS card to patch panel, following the scheme below.

	Warning
	Using the “straight” scheme of connection, crosstalk issues occur in the part of cable from the patch panel to phones.

Figure 3.5. Adapter cable

Using a “straight” cable crosstalk issues occur because pair #3 couples conductors #3,6 and pair #1 couples conductors #4,5. Crosstalk issues are located in the part of cable from the patch panel to phones.

Figure 3.6. “Straight” scheme of connection - Conductors affected by crosstalk