> ## Documentation Index
> Fetch the complete documentation index at: https://docs.solidyne.ar/llms.txt
> Use this file to discover all available pages before exploring further.
# Mounting and rear panel
> Description of mounting and rear panel connectors
## Mounting Recommendations
* The unit is designed for mounting in a **standard 19" rack**. Requires 1U height.
* If placing the unit on a shelf, attach the factory-supplied **rubber feet** to the base.
* Do not place the unit on an unstable surface or shelf; it could fall, causing damage to people and equipment.
* The **ambient temperature** must be between **5ºC and 40ºC**.
* Avoid direct sunlight or proximity to heat sources.
* The 542APC has **internal RF field protection**, allowing mounting near transmitters.
* Avoid strong electromagnetic fields (transformers, motors, etc).
Place the equipment on a stable surface in a controlled environment. Avoid direct heat, electromagnetic fields and vibrations.
### Rack Mounting
* The unit does not use forced ventilation. Leave one rack unit of free space below and above the processor to facilitate heat dissipation.
* Always use **flat head screws** with **flexible washers** (plastic or rubber).
* Tighten the **lower** screws first, then the **upper** ones, to prevent the unit's weight from creating leverage on the upper angles.
* Do not apply excessive force when tightening. Light pressure is sufficient to secure the unit.
Excessive pressure on the screws can deform or even break the front panel angles.
***
## Power Supply
* The unit works with **manual voltage selection** between **200/240V or 100/130V**.
Verify the correct position of the **voltage selector** on the rear panel.
* Mains voltage must remain within a variation margin less than **10%**.\
Otherwise, use fast-action stabilizers (ferroresonance or electronic).
* Power is controlled through the **main switch**.
* The unit has a **1A main fuse**.
Do not use adapters that bypass the ground pin of the Interlock cable. \
The entire installation must have proper **grounding**.
It is recommended to follow regional grounding standards.
* **USA:** NEC Article 810; ANSI/NFPA No. 70-1984
* **Argentina:** IRAM 2379 and 2281-3
The power cable should not be installed alongside audio cables, especially those carrying analog audio.
***
## Rear Panel Connectors
1. Mains **voltage selector** switch.
2. Power Interlock.
3. **Power** switch.
4. Main fuse (1A)
5. Balanced **analog inputs** **XLR**.
6. Balanced **analog inputs** **RJ45**
7. **Digital input** AES3
8. **Digital output** AES3
9. Balanced **analog outputs** **XLR**
10. **Analog outputs RJ45** (unbalanced)
11. Ethernet port for **web control**.
12. **MPX** composite outputs for FM (independent levels) (BNC)
13. External **antenna** for tuner (BNC)
14. **GPIO** (DB9)
15. Ethernet port for **audio stream** link
16. Reserved for future use.
## FM Receiver Antenna
The 542APC's internal receiver allows:
Tuning to any station's transmission.
Displaying modulation level, audio levels and RDS information, among other parameters.
### Antenna Connection
The **Receiver FM ANT** connector is **BNC** type.
Two antennas are supplied from factory:
* **Extendable mini telescopic antenna**
* Suitable for most installations.
* **BNC micro-antenna**
* Recommended when RF field strength is very high.
* The telescopic antenna could cause tuner saturation (the **RF LVL** indicator on the FM Monitor Analyzer stays fixed at *100 dBuV*).
* In this case, use the lower-gain BNC micro-antenna.
### External Antennas
Depending on installation conditions (equipment location, distance to transmitter plant, etc.), installing an external **FM antenna** may be convenient.
External antennas are not included with the equipment.