Manual call point MHA 904 is equipped with 2 change-over reed switches with two stable states that switch simultaneously, and with twocolour LED signalling state of the manual call point or an external device. One change-over contact can switch up to 0,5 A, the other one, power, can switch up to 3 A. The manual call point contains a terminal base to which the change-over contacts and two-colour LED are connected.
| Manual call point comes in following colour variant. |
| Red | 6XK 053 340 | Without label |
| Green | 6XK 053 341 | Without label |
| Blue | 6XK 053 342 | Without label |
| Yellow | 6XK 053 343 | Without label |
| On customers demand a custom label can be added. |
To terminal base 1, 2 and 3 on XT1 is connected power change-over reed switch 3 A which is controlled by manual call point’s magnet. In normal state (button not pressed) are connected terminals 1 and 2, in activated state (pressed button) are connected terminals 1 and 3.
To terminal base 1, 2 and 3 on XT2 is connected a change-over reed switch 0,5 A which is controlled by manual call point’s magnet. In normal state (button not pressed) are connected terminals 1 and 2, in activated state (pressed button) are connected terminals 1 and 3.
Terminal base XT3 has 6 terminals marked from 1 to 6. Terminals 1-5 serves for connection of two-colour LED. Terminal 6 is free and can be used for example for connection of shielding.
| Connection of two-colour LED: |
| Terminal XT 3 | Meaning |
| 1 | common – minus |
| 2 | + 12 V green colour |
| 3 | + 24 V green colour |
| 4 | + 12 V red colour |
| 5 | + 24 V red colour |
