Introduction and Features
System Introduction
The GXC Onyx FHM 5G Fronthaul Multiplexer is an AC-Powered, high-performance, versatile open networking fronthaul device that is designed to expand coverage and maximizes DU resources with flexibility as service providers improve their services. Implementing O-RAN’s shared cell function, the Onyx FHM enables optimization of the user’s private 5G network by utilizing DU resources efficiently and streamline the upgrading process when increasing service capacity.
The Onyx FHM is future-proofed with a powerful 4-core processor, a programmable FPGA, 10GE/25GE interfaces, and full timing features supporting IEEE 1588v2 and SyncE. It is suitable for indoor and outdoor cabinet deployments with redundant, hot swappable components for convenience, increased availability, reliability and lower costs of maintenance.
This document describes the hardware installation process for the Onyx FHM.
System Package Contents
Check your system package for the following items.
System Package Contents
1
Onyx FHM Chassis without PSU
17.32” x 9.84” x 1.71” (440 x 250 x 43.5mm)
1 pc.
9.22 lbs. (4.18kg)
2
AC Power Supply Unit (PSU)
1.99” x 8.31” x 1.58” (50.5 x 211.0 x 40.2mm)
2 pcs.
1.58 lbs. (0.72kg)
3
Grounding Lug
1.97” x 0.44” x 0.30” (50.0 x 11.1 x 7.5mm)
1 pc.
0.022 lb. (10.0g)
4
Grounding Lug Screw Kit
2X Screws M4, 8.0mm Long 4X M4 Lock Washers
1 set
0.01 lb. (3.5g)
5
19-inch Rack Mount Bracket
1.98” x 1.69” x 0.79” (50.4 x 43.0 x 20mm)
2 pcs.
0.07 lb. (32.7g)
6
Rack Mount Bracket Screw Kit
8X Screws M4, 6.5mm Long
2 sets
0.02 lb. (7g)
7
USB 2.0 Type-A Cable
7.87” (200mm)
1 pc.
0.023 lb. (10.5g)
8
AC Power Cord
72.05” (1830mm)
2 pcs.
0.46 lb. (207g)
9
RJ45 to DB9 Female Cable
95.98” (2438mm)
1 pc.
0.23lb. (105g)
10
Screw Kit
2X Screw M4, 25mm Long 2X Dia. 8mm x 25mm Long
2 sets
0.009 lb. (4.50g) 0.005 lb. (2.25g)
GXC Onyx FHM (Fronthaul Multiplexer) Dimensions

GXC 5G Onyx Platform Architecture

Onyx FHM - Front Panel View
Onyx FHM - Front Panel View

Onyx FHM - Rear Panel View
Onyx FHM - Rear Panel View

AC PSU Overview
Power Supply Unit (PSU) with 1+1 redundancy. Hot swappable, field replaceable unit (FRU).
PSU Dimensions and Details

Preparation
Environmental Requirements
In addition to network planning, when determining where to place the GXC Onyx FHM you need to consider factors such as climate, hydrology, geology, the possibility of earthquakes, reliable electric power, and transportation access.
Avoid locating the unit in areas where there may be extreme temperatures, harmful gases, unstable voltages, excessive vibrations, open flames, explosives, or electromagnetic interference (e.g., large radar stations, transformer substations). Avoid areas prone to impounded water, soaking, leakage, or condensation. The following table lists the environmental specifications.
Environmental Specifications
Operating Temperature
-40° to 65°C / -40 to 149°F
Relative Humidity
5 % to 95 % RH (non-condensing)
Atmospheric Pressure
70 kPa to 106 kPa
Operating voltage
100 to 240VAC (Universal)
Typical Power Consumption
300W (max typical)
Mounting Considerations
The GXC Onyx FHM has a unit width of 17.32 inches (440mm), as shown above. The unit ships with rack mount brackets suitable for EIA-Standard 19-inch (483 mm) racks. The rack mount brackets can be installed at the front or in the center of the unit.
The depth of the Onyx FHM chassis is 9.84 inches (250mm) without the field replaceable PSUs. To accommodate the air inlet and front cabling, a minimum clearance of 6 inches (152mm) in front of the unit is specified, thereby making the minimum reserve depth 15.84 inches (402.3mm).
The 19-inch Rack Mount Brackets included with the GXC Onyx FHM can be utilized to mount the unit in two different positions relative to the front of the unit.
The Front Mount Approach is more commonly used for rack-mounted equipment. However, this mounting approach results in increased stress on the mounting brackets due to the center of gravity of the unit being behind the mounting point. These stresses can be resolved by installing the unit directly above other equipment that is supported by rear posts of a 4-post rack or the use of a 1U Rack Shelf.
Alternatively, a Center Mount Approach can be used for the GXC Onyx FHM. In this approach, the 19-inch Rack Mount Brackets are affixed to the unit at the center of depth mounting location. This approach reduces stress on the mounting brackets by mounting the unit at a depth very close to its center of gravity. However, utilizing this mounting approach causes the front of the Onyx FHM to protrude from the front of the rack by approximately 4.40 inches (112mm).
The following figure depicts typical Front Mount and Center Mount orientations for the GXC Onyx FHM in a 19-inch rack.
Onyx FHM Mounting Approaches and Critical Dimensions

Optical Port Overview
The following table and figure are meant to help the installer and user of the Onyx FHM in identification of the various optical ports, specify the maximum supported communication distances and the supported connection speeds.
Optical Port Specifications
0 - 7
SFP28
6.21mi (10km)
10/25G
8 - 11
SFP28
6.21mi (10km)
10/25G
12 - 13
QSFP28
6.21mi (10km)
40/100G
Optical Port Identification

Equipment Cooling
The GXC Onyx FHM utilizes internal fans to intake air from the front to cool the internal electronics. Heat is transferred to this air and then exhausted out the back of the unit. Care should be taken during installation to ensure that adjacent equipment in the same rack uses this same front-to-back airflow orientation.
CAUTION: Failure to ensure adjacent equipment utilizes a front-to-back airflow orientation can lead to elevated intake air temperatures, a reduction in the operational air temperature margins, and possible reductions in operation stability of the Onyx FHM.
Figure: Front-to-Back Airflow Depiction

The GXC Onyx FHM requires clearance at the front and back of the unit to ensure adequate airflow to the unit. Care should be taken to avoid equipment cables or other materials from blocking both the intake and the exhaust vents to the unit.
Onyx FHM Front and Back Airflow Clearances

Grounding Protection
You must protect the GXC Onyx FHM against accidental electrostatic discharge (ESD) or shortage of power to ground. The following guidelines concerning grounding must be followed.
In addition to the AC Line Ground (Signal Ground), a discrete Earth Ground shall be provided and terminated using the provided 2-Hole Compression Lug (0.625-inch (16mm) lug-to-lug spacing). This grounding lug and its associated M4 mounting screws and lock washers are included with the Onyx FHM. The installer must provide a 6 AWG Grounding Cable which will be terminated to the lug and attached to the unit where shown.
Grounding Lug Hardware Assembly Detail

Grounding Compression Installation Location Detail

Details regarding installation of the Ground Lug shall be provided in the Installation Section of this document.
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