What does the impedance check's odd/even error mean?

This error occurs when only the odd or only the even numbered channels are enabled or gelled using SAGA.

During an impedance check, the impedances are shown through color-coded indicators. When an odd/even error occurs, the color indicators of all electrodes turn pink and the impedance value is  5100 kΩ.

For the TMSi gel headcap, the Odd/Even error occurs when only the odd or only the even channels are gelled. When this error occurs, the color for the impedance check of all electrodes turns pink. To prevent this error, at least one odd (1, 3, 5 etc) and one even numbered channel (2, 4, 6 etc) connected to the subject should be gelled. Once both an odd and an even channel are gelled, the error should disappear.

For a water headcap, the same error occurs when only the odd or even water-based electrodes are wet.

When using a few channels, it could be that one of the even/odd channels is not making appropriate contact, which results in a similar error as well.

The table below shows the electrode position's channel number, to help find the odd and even numbered channels.