Short answer: Existing Somfy RTS shades join Control4, Crestron or Savant without new motors. Use the Universal RTS Interface II (1810872) for serial control: 16 RTS channels per unit over RS232, RS485 or IR, up to 256 channels. Use the TaHoma Switch (1871037) for IP control: 40 RTS channels plus 60 Zigbee products.
The homeowner already paid for the shades. They want them on the touch panel by the time the theater is done. Quote new motors and you lose the job to the integrator who quotes an interface. Every RTS motor accepts more than one transmitter, so the control system pairs in as one more remote and the original remotes keep working. Your only real decision is the bridge.
Free spec package
Somfy RTS control system integration spec package
- Decision table: URTSI II, TaHoma Switch or UAI Plus
- Riser for a serial and an IP integration
- Editable 3-part guide specification
- Channel map template and retrofit checklist
Confirm the motors before you quote
Somfy runs two motor networks on residential and light commercial jobs, and each one takes a different interface. RTS motors listen on 433.420 MHz radio. SDN motors run wired RS485. A site walk that misses the difference turns into a second trip and a change order.
Check the remotes and the motor labels. Telis, Situo and DecoFlex RTS controls point to RTS. A keypad on a Cat 5 drop and a power panel in the closet point to SDN. Count the shades, count the groups the client wants on screen, and note any shade that only moves with its neighbor. That count sets the channel budget.
URTSI II: the serial route
The Somfy Universal RTS Interface II (1810872) converts RS232 and RS485 commands into RTS radio. It also accepts IR. One unit carries 16 RTS channels, and you cascade up to 16 units for 256 channels. Somfy rates it compatible with every RTS motor and receiver, across shades, draperies, awnings, screens, pergolas and rolling shutters.
Pick URTSI II when the processor has a free serial port, when the client wants no dependency on Wi-Fi, or when the channel count runs past 40. Mount it central to the shades it controls. RTS radio does not need line of sight, but concrete and metal both cut range, so test every channel from the final mounting spot before you close up a wall.
TaHoma Switch: the IP route
The Somfy TaHoma Switch (1871037) runs up to 40 RTS channels and up to 60 Zigbee products from one hub on the network. Somfy lists integration with Control4, Crestron, Savant, ELAN, URC, RTI and Josh.ai. On Control4, the TaHoma driver pulls in the RTS channels and the scenes you build in the TaHoma app.
Rack it on a wired drop when you can. The TaHoma Switch with Ethernet Adapter (1871038) gives you a hard connection instead of Wi-Fi, which matters in an equipment closet full of metal. TaHoma also suits the job where the client wants app control and voice alongside the touch panel, and where new Zigbee shades may join later.
The SDN exception: UAI Plus
Wired SDN motors skip both of those. The Somfy Connect UAI Plus (1870272) commissions and integrates up to 250 SDN motors over IP through the Somfy Synergy API, with drivers for Control4, Crestron and Savant. On Control4 it reports motor position on OS 2.9 or higher. RTS radio carries commands one way, so position feedback is the line item that separates an SDN design from an RTS retrofit. Sell feedback on new construction. Sell the interface on retrofit.
URTSI II or TaHoma: the decision table
Pick fast
- Up to 16 channels, processor has RS232: one URTSI II.
- 17 to 256 channels on serial: cascade URTSI II units, 16 channels each.
- Up to 40 RTS channels, IP-only processor or app control wanted: TaHoma Switch, Ethernet version in a rack.
- Future Zigbee shades on the same job: TaHoma Switch, up to 60 Zigbee products.
- Wired SDN motors with position feedback: UAI Plus, up to 250 motors.
- Existing myLink on Control4: Somfy's myLink driver supports firmware 4.06 or higher on OS 2.6 and up, so it can stay.
Pairing and the channel map
Each interface channel pairs to a motor the same way a new remote does: put the motor in programming mode from a remote it already knows, then confirm from the new channel. Pair one channel per group, and pair individual shades only when the client will use them. Every extra channel is one more button to program and support.
Write the channel map before you touch a motor: channel number, room, shade names, the remote that already controls them. Leave the map in the panel and in the client file. A shade added next year, such as a Somfy Sonesse 30 RTS 24V DC motor (1241142), pairs to an open channel in minutes when the map exists. The spec package below includes a blank map.
Order list for a typical retrofit
A 12-shade house with eight groups needs one URTSI II on serial or one TaHoma Switch on IP. A 30-shade house with 22 groups needs two cascaded URTSI II units, or one TaHoma at 22 of its 40 channels. Order the interface, a serial cable for the processor if you go URTSI, and a spare RTS remote for the client so a lost handset never means a service call.
Take the spec package to your submittal
Somfy RTS control system integration spec package
- Decision table: URTSI II, TaHoma Switch or UAI Plus
- Riser for a serial and an IP integration
- Editable 3-part guide specification
- Channel map template and retrofit checklist
FAQ
Can I add a control system to existing Somfy RTS shades without replacing the motors?
Yes. RTS motors accept more than one transmitter, so an interface pairs to each motor or group as one more remote. Use the URTSI II (1810872) for serial control or the TaHoma Switch (1871037) for IP control. Existing remotes keep working.
How many shades can one URTSI II control?
One URTSI II carries 16 RTS channels. Each channel can control one shade or a group of shades paired to it. Cascade up to 16 units for 256 channels. The interface accepts RS232, RS485 or IR commands and works with all Somfy RTS motors and receivers.
Does TaHoma Switch work with Control4, Crestron and Savant?
Somfy lists TaHoma Switch integration with Control4, Crestron, Savant, ELAN, URC, RTI and Josh.ai. It supports up to 40 RTS channels and 60 Zigbee products. On Control4, the TaHoma driver exposes the RTS channels and scenes created in the TaHoma app.
Do Somfy RTS shades report their position to the control system?
RTS radio sends commands one way, so the control system tracks commands it sent rather than confirmed positions. For position feedback, specify wired SDN motors with the UAI Plus (1870272), which reports motor position on Control4 OS 2.9 or higher.
Sources: Somfy Universal RTS Interface II product page (1810872); Somfy TaHoma Switch product page (1871037); Somfy Connect UAI Plus product page (1870272); Somfy Control4 integration page, somfysystems.com.
Ryan Towns writes the Somfy Integrator Guides for ShadeMotorsDirect, an authorized Somfy distributor. Questions on a spec or a retrofit: 859-414-6872 or colin@shademotorsdirect.com, 8:00 AM - 7:30 PM ET.
