Short answer: The Somfy SDN Data Hub V2 (1870951) is a bus distribution device for the Somfy Digital Network. It adds 5 RJ45 device ports to an SDN bus line and supports wiring stubs up to 200 ft. It runs on 24V DC bus power unless two or more motors sit on its ports, and it can power 3 keypads or 1 RTS receiver.
Placing a Data Hub on an SDN job
An SDN system runs motors, keypads and interfaces on one wired, addressable bus. The bus line is the trunk. Devices hang off it, and the Data Hub is the junction box that gives you somewhere to plug them in. Somfy calls the Somfy SDN Data Hub V2 (1870951) the backbone of its SDN Connect range, and the job is narrow: take one bus line and break out five device ports along it.
Installers reach for it at a cluster. A conference room with four shades and a keypad by the door is the classic case. Drop a Data Hub above the ceiling near the window wall, home-run one bus line to it, and land the motors and the keypad on its ports with short RJ45 stubs. The alternative is a long chain of splices that gets harder to trace with each shade.
The Data Hub V2 is a wired SDN part. It suits interior blinds, draperies and shades on RS485 motors such as the Sonesse 30 RS485 and Sonesse 40 RS485. It does not talk to RTS or Zigbee motors by radio.
Verified specs for the Data Hub V2
The figures below come from Somfy's own product pages for reference 1870951 on somfysystems.com and somfypro.com.
| Somfy name | SDN Data Hub V2 |
| Somfy reference | 1870951 |
| Function | SDN bus distribution, adds 5 device ports to an SDN bus line |
| Power supply | 24V DC bus power, or powered by motors when 2 or more motors connect to its device ports |
| Can power | 3 keypads or 1 RTS receiver |
| Connectors | RJ45 |
| Wiring stub length | Up to 200 ft |
| Status indicators | Bus segment LEDs for power, activity and end of line |
| Test function | Sequence button to test motor operation at the hub |
| Mounting | Mounting clip option for installation and removal |
| Protection index | IP 20 |
| Insulation class | Class I |
| Technology | Wired (SDN) |
| Applications | Interior blinds, draperies and shades |
| Warranty | 5 years |
IP 20 means a dry, indoor location such as a closet or a ceiling cavity. Keep it out of exterior soffits and any spot that sees condensation.
Bus power or motor power
The power rule is the spec that changes the bill of materials. Somfy publishes it in one line: the Data Hub V2 draws power from the motors when two or more motors connect to its device ports, and otherwise it requires bus power.
Plan it per hub. A hub feeding three motors and a keypad can run from those motors. A hub that only breaks out keypads, or one motor and a keypad, needs 24V DC on the bus. The usual source is the Somfy Bus and Sensor Station Power Supply (1822440). Somfy rates it to supply 24V DC to the SDN bus for up to 80 bus line devices, motors excluded, from a 100 to 240 V input.
Somfy also cites reduced power consumption on the V2, which gives a designer room to add devices to a bus segment at the design stage. Our bus power supply guide covers the supply's modes and wiring.
Five device ports and the 200 ft stub
Each device port takes an RJ45 stub up to 200 ft long. That reach covers most rooms from a single hub location, so you can mount the hub where a technician can reach it, not where the window happens to be.
The Data Hub can feed power to the devices it serves, within a firm limit. Somfy rates it for 3 keypads or 1 RTS receiver. Treat that as a design ceiling. If a room needs a fourth keypad, put it on a second hub or a powered port.
Motors connect to device ports too, and two or more of them on one hub lift the bus power requirement for that hub. Motors and keypads can share one Data Hub. Somfy publishes a wire detail drawing for the hub (DH-WIRING-01); follow it for the connections. The install guide and wiring detail sit in our Somfy spec sheet library.
Data Hub V2 or the PowerConnect panel
The Data Hub has a bigger sibling. The Somfy SDN PowerConnect Surface-Mount Panel (1871026) adds 10 isolated motor ports and two isolated device ports to an SDN bus segment. Its motor ports support up to 240 ft of power and data wiring to each low-voltage motor, and internal power supplies feed its device ports.
The split comes down to who supplies motor power. The panel powers motors from its own supplies. The Data Hub distributes the bus and takes its own power from motors or a bus supply. Choose the panel where motors need power at the distribution point, and the Data Hub where a bus line needs extra device ports near a group of shades.
Somfy notes the panel can run a small SDN system alone, with two control devices and 10 motors. On a project that size, the panel may be the only distribution part you buy. Past 10 motors, or with keypads spread across several rooms, Data Hubs earn their place.
Commissioning and testing at the hub
The Data Hub V2 carries two features that save a ladder trip. The sequence button tests motor operation straight from the hub, so a technician can confirm the motors on its ports respond before the ceiling closes. The bus segment LEDs show power, activity and end of line at a glance.
Addressing and limit setting happen with separate tools. The Somfy RS485 Setting Tool (9017142) is the hand-held motor setting and address reader Somfy lists as required to set limits on RS485 motors. For laptop work, the Somfy USB to RS485 Adaptor (9015260) connects a PC to the bus. Somfy lists the SDN Set pro user guide among the Data Hub V2 documents, and our USB to RS485 commissioning guide walks through that connection.
Comparing platforms before you commit? Our Somfy control systems comparison lines up SDN against RTS, Zigbee and plain wired control. The rest of the range sits with our Somfy smart hubs and network interfaces.
Frequently asked questions
Does the Somfy Data Hub V2 need its own power supply?
It depends on what sits on its ports. Somfy states the Data Hub V2 draws power from the motors when two or more motors connect to its device ports. With fewer than two motors attached, it needs 24V DC bus power, usually from the Somfy Bus and Sensor Station Power Supply (1822440). Plan the power source hub by hub during design.
How many keypads can a Data Hub V2 power?
Somfy rates the Data Hub V2 to power 3 keypads or 1 RTS receiver. Treat that figure as the design limit for each hub. A room that needs a fourth keypad calls for a second Data Hub or a port with its own supply, such as a device port on the SDN PowerConnect Surface-Mount Panel (1871026).
How long can the cable runs from a Data Hub V2 be?
Somfy publishes a wiring stub length of up to 200 ft from the Data Hub V2, on RJ45 connectors. That reach lets an installer mount the hub in an accessible ceiling or closet and run stubs out to the shades and keypads. Somfy's wire detail drawing DH-WIRING-01 shows the connections.
Does the Data Hub V2 work with RTS or Zigbee motors?
The Data Hub V2 is a wired SDN device for RS485 motors such as the Sonesse 30 RS485. It does not drive RTS or Zigbee motors by radio. Somfy rates it to power one RTS receiver on the bus. For RTS or Zigbee motors with no SDN wiring, the TaHoma Switch is the Somfy hub to look at instead.
Sources: Somfy product pages for the SDN Data Hub V2 (ref. 1870951) on somfysystems.com and somfypro.com, the SDN PowerConnect Surface-Mount Panel (ref. 1871026), the RS485 Motor Limit Setting and Address Reader Tool (ref. 9017142) and the Bus and Sensor Station Power Supply (ref. 1822440) on somfysystems.com.
Shade Motors Direct is an authorized source for genuine Somfy motorized window shade, blind, and drapery parts.
