The main power input on Tekron clocks use three different connector styles. The table below shows the Input Power connector types used.
| Power Connector Type | Image | Use |
| IEC |  |
For AC mains supply. |
| 2 Pin |  |
For DC power supply. |
| 3 Pin |  |
For AC & DC power supply. |
For the DC power supply input, most Tekron clocks are polarity insensitive, meaning that it does not matter which way around the '+' and '-' terminals are connected. In the voltage power supply input, there is a full-wave rectifier which removes the polarity sensitivity. However, there are some legacy Tekron clocks which are polarity sensitive. This guide details the input power polarity for DC supply for all Tekron clocks.
| Clock Model | Polarity Sensitive | Image | Description |
| TSC100 / NTS 100 | Yes |  |
There should be a + and – symbol etched below the power connector, indicating the power polarity. |
| PRPTP | Yes |  |
There should be a + and – symbol etched below the power connector, indicating the power polarity. |
| NTS 01 | No |  |
Despite the + and O symbols above the power connector, there is no power input polarity. |
| NTS 02-E / NTS 02-G | No | |
DC power should be applied to pins L and N. DC polarity is not critical, but only pin L is fused internally. We recommend connecting the '+' terminal to L. Do NOT connect anything to pin E for supplying DC power. This PWR input can also be used for AC supply. E is the Earth connection for AC supply. |
| NTS 03-E / NTS 03-G | No |  |
|
| TCG 01 / TCG 01-E | No |  |
There should be a + and o symbols above the power connector, there is no power input polarity. |
| TCG 01-G | No |  |
|
| TCG 02-E | No |  |
There should the + and - symbols below the power connector, there is no power input polarity.
|
| TCG 02-G | No | |
|
| TTM 01-E | No |  |
There should be + and 0 symbols above the PWR input, there is no power input polarity. |
| TTM 01-G / PTP Translator | No |  |
There should be + and - symbols above the PWR input, there is no power input polarity. |
| ITR | No | |
Despite the + and - / + and 0 symbols above the PWR input, there is no power input polarity. |
| MOFR 01 | Yes | |
There should be a + and – symbol etched above the power connector, indicating the power polarity. |
| ITD | Yes |  |
There should be a + and – symbol etched below the power connector, indicating the power polarity. |