Somfy URTSI II

Driver for the Somfy URTSI II (Universal RTS Interface II) — the wall- or rack-mount box that turns serial commands into Somfy RTS radio signals. One URTSI II drives up to 16 RTS motor channels, so it is the standard way to put a bank of RTS roller shades, drapery tracks, exterior screens, or awnings under GEM control without a radio per shade.

The URTSI II itself is a serial device (RS-232 / RS-485). GEM talks to it over plain TCP, so in almost every install the URTSI II sits behind a serial-to-IP adapter — a Global Caché iTach, a Brainboxes, or any raw-TCP serial gateway — and GEM connects to that adapter's IP and port. Because one URTSI II addresses many motors, you add it once as a device and then create one zone per RTS channel.

RTS is one-way radio

RTS is a send-only protocol. GEM can raise, lower, and stop a shade, but the motor never reports its position back. GEM tracks only the last command it sent — see What GEM knows — and what it doesn't.

Prerequisites

• Program each RTS motor onto its URTSI II channel first. Using the URTSI II's own front-panel buttons, walk each shade motor through the RTS pairing/limit procedure in Somfy's URTSI II setup guide so it responds on a specific channel (1–16). GEM controls channels the URTSI II already owns; it does not pair motors.
• Set the motors' travel limits and direction on the motor itself (with a Somfy remote or the URTSI's programming mode) before wiring up GEM. GEM only sends up / down / stop — it cannot set limits.
• Put the URTSI II behind a serial-to-IP adapter and note the adapter's IP address and raw-TCP port (for a Global Caché iTach the serial port is commonly 4999). Configure the adapter's serial port to match the URTSI II's serial settings — per Somfy's documentation this is typically 9600 baud, 8 data bits, no parity, 1 stop bit. If the baud or framing don't match, the URTSI II ignores everything and the shades never move.
• Leave the URTSI II at unit address 01. This driver always addresses URTSI unit 01 (the factory default). If you have re-addressed the URTSI II front panel to another unit id, GEM will not reach it.
• Network: give the adapter a static IP or DHCP reservation and make sure its TCP port is reachable from the GEM host.

Setup — add the URTSI II

1. Go to System → Devices → Add Device and set:
   • Driver → Somfy URTSI II. GEM pre-selects the Controller device type.
   • Adapter IP → the LAN IP of the serial-to-IP adapter fronting the URTSI II (not the URTSI II itself — it has no IP of its own).
   • TCP Port → the adapter's raw serial-passthrough port (e.g. 4999 on a Global Caché iTach).
2. Enable the device. GEM opens a persistent TCP connection to the adapter and holds it open, reconnecting automatically with a backoff if the link drops. There is no login — the URTSI II protocol is unauthenticated.
3. There is nothing to "discover." The URTSI II does not report which channels are in use, so GEM cannot build zones for you — you create them by hand in the next step.

tip

Tip — you can enter the address as ip:port

If you leave Adapter IP and TCP Port blank but set the device Address to 192.168.1.50:4999, GEM splits it into the IP and port for you on first connect. Filling the two fields explicitly is clearer, but either works.

Zones — one per RTS channel

Each RTS channel on the URTSI II becomes one GEM zone.

1. Open the URTSI II device's Zones tab (or System → Zones → Add) and add a zone for each channel you programmed.
2. GEM pre-selects the Shades subsystem for you. Set Control to Shade so the zone renders the shade control (Open / Close / Stop) in UIs.
3. Set Address to the URTSI II channel number, 1–16. A one- or two-digit value is fine — GEM zero-pads it to two digits when it sends the command, so 1 and 01 behave identically.

That is all a shade zone needs. The standard Open, Close, and Stop buttons work immediately — see below.

How control works

Every zone command is sent to the URTSI II as a short ASCII string terminated by a carriage return, in the form 01 + two-digit channel + command letter:

You press / call	Sent to the URTSI II	RTS action
Open (open / up)	0103U (channel 3)	Raise / open
Close (close / down)	0103D (channel 3)	Lower / close
Stop (stop)	0103S (channel 3)	Stop mid-travel

The leading 01 is the URTSI unit address (fixed at 01); the middle two digits are the zone's Address; the letter is the motion. GEM fills the channel in from the zone's Address automatically, which is why the on-screen buttons work with no extra configuration. Commands are paced a fraction of a second apart, so a macro that moves several shades at once is sent to the URTSI II in an orderly sequence rather than all at once.

open and up are the same command, as are close and down — the extra verbs exist so RTS terminology (up / down / stop) is available in macros and the command tester alongside GEM's shade verbs (open / close / stop).

One URTSI II = 16 channels

If a site has more than 16 RTS shades, add a second URTSI II as its own device (behind its own adapter port) and split the channels across the two.

Device attributes

Attribute	Set by	Purpose
ip (Adapter IP)	You	LAN IP of the serial-to-IP adapter connected to the URTSI II. Use a static IP or DHCP reservation.
port (TCP Port)	You	Raw-TCP serial-passthrough port on the adapter (e.g. 4999 on a Global Caché iTach).

The driver inherits the generic TCP advanced fields (reconnect timing, command throttle, keep-alive ping) but the URTSI II needs none of them — leave them at their defaults.

Zone attributes

Attribute	Purpose
Address	The URTSI II channel number, 1–16. Required — this is how a zone's Open / Close / Stop reach the right motor. Zero-padded to two digits automatically.

Command reference

Run these from the device's Commands tab (the command tester), from macros, or from UI buttons. The driver declares exactly these five commands, each taking the channel from the zone's Address:

Command	Sent	Action
open	01<ch>U	Open / raise the shade (RTS up).
up	01<ch>U	Alias of open.
close	01<ch>D	Close / lower the shade (RTS down).
down	01<ch>D	Alias of close.
stop	01<ch>S	Stop the shade mid-travel (RTS stop).

There is no "go to 50 %" or preset-position command — RTS motors expose only up / down / stop over the URTSI II. If your motors have a Somfy "my" favorite position programmed, a brief stop while the shade is idle recalls it on most RTS motors; that behavior comes from the motor, not from GEM.

What GEM knows — and what it doesn't

The URTSI II integration is open-loop. RTS is a one-way radio protocol: the URTSI II transmits commands but receives nothing back from the motors, so GEM has no way to read a shade's real position. A shade zone reflects only the last command GEM sent — it will not update if someone moves that shade with a handheld Somfy remote, and it cannot show a partial position. For predictable state, drive the RTS shades from GEM (or from scenes GEM triggers) rather than mixing in manual remote operation.

Troubleshooting

Symptom	Check
Nothing moves, device shows connected	Confirm the adapter's serial settings match the URTSI II (commonly 9600 / 8-N-1) and that its serial cable/wiring is correct. GEM being "connected" only proves the TCP link to the adapter is up, not that the serial side is talking to the URTSI II.
One shade won't respond, others do	That channel isn't programmed on the URTSI II, or its motor lost its limits/pairing. Re-run the motor's RTS setup and confirm the channel from the URTSI II front panel.
A shade opens when you press Close (or vice-versa)	The motor's rotation direction is reversed. Fix it on the motor (Somfy remote / URTSI programming), not in GEM.
Wrong shade moves	The zone Address doesn't match the URTSI II channel that motor is on. Correct the zone Address to the right 1–16 channel.
Never connects	Verify the Adapter IP and TCP Port point at the serial-to-IP adapter, that the port is reachable from the GEM host, and that no other software is already holding that serial port open.
Whole URTSI II is unreachable but the adapter pings	The URTSI II may have been re-addressed off unit 01. This driver only talks to unit 01 — reset the URTSI II unit address to 01.
stop seems to do nothing	RTS stop only acts while the motor is moving. Pressing Stop on an already-stopped shade has no visible effect (or recalls the motor's "my" position, if one is set).

Related documentation

• Devices — add the URTSI II controller and set its Adapter IP / TCP Port.
• Zones — create one Shade zone per RTS channel and set its Address.
• Subsystems — the Shades subsystem these zones land in.
• Commands — where open, close, stop, up, and down appear and can be tested.
• Macros — sequence shade moves (e.g. an "All shades down" scene) from automations and UI buttons.