RailBOX RB1110 / RB1110-Mini

Reference for the Wi-Fi DCC command station RB1110 and its compact variant RB1110-Mini, in the context of the BigFred hub. Manufacturer documentation: RailBOX RB1110 PDF.

BigFred terminology: command station / centralka — see 00-terminology.md.

1. Role on the layout

The RB1110 is a DCC command station (centralka): it generates DCC on the track, manages locomotive slots, and exposes several industry protocols for handhelds, feedback modules, and PC/tablet software.

In a BigFred deployment the Pi host runs loco-server and one dcc-bus daemon per attached command station. Drivers use the web UI; the daemon talks to the RB1110 over the network — there is no USB cable from the Pi to the central on the supported path.

Browsers ──HTTP/WS──► loco-server (e.g. Raspberry Pi 5)
                          │
                          ▼
                     dcc-bus ──► UDP Z21 (port 21105)
                          │
                     RB1110 (WiFi / home network)
                          │
                          └──► DCC track ──► layout

Integration details shared with the LocoNet-adapter doc set: 07-z21-command-stations.md.

2. Models

Both models include: XpressNet, s88-N, RS-Bus, LocoNet (RJ12), USB-C, and a built-in Wi-Fi module.

3. Technical specifications

3.1 Load and current capacity

The maximum instantaneous load on the command station is 3 A. With a single booster this limits how many trains and accessories can run at once.

Typical current draw (manufacturer figures):

With several sound-equipped locomotives it is easy to approach the 3 A limit — then an additional DCC booster is needed (e.g. a RailBOX unit with LocoNet).

Locomotive slots (60) are the command station's logical limit (active addresses on the DCC bus), independent of the ampere limit. BigFred does not impose its own slot limit beyond what the command station provides.

4. Supported protocols

The command station implements the protocols listed by RailBOX (trademarks belong to their respective owners):

4.1 Physical connections

Manufacturer warning: do not use track clips with a built-in capacitor (e.g. Piko 55270) — they are intended for DC, not DCC pulse power; they can damage the command station.

5. RailCom and DCCA

The RB1110 has a RailCom receiver and supports DCCA (NMRA S-9.2.1.1 — dynamic addressing):

• Automatic detection of new RailBOX decoders (marked “Easy configuration”) when connected to the main track.
• CV read/write on the main track (PoM) without a programming track.
• Dynamic addressing — the command station assigns a free address based on the decoder's serial number; the same decoder can have a different address on another command station (useful at exhibitions).

These features are primarily delivered by the RailBOX: Railroad Control app. BigFred does not implement automatic RailCom/DCCA address assignment — it uses static DCC addresses configured in the vehicle catalogue.

Exhibition / multi-central tip (RailBOX, forum): when locomotives already have fixed addresses, disable “decoder detection system” in the app — dynamic RailCom/DCCA assignment is unnecessary and can interfere with adding locos after a firmware update (e.g. loco reads CV on the programming track but does not respond on the main track).

Recent firmware/app releases (manufacturer posts, 2025–2026):

Work is ongoing on automatically importing decoders already stored in the command station memory into the app.

6. Wi-Fi — network setup

The command station has a built-in Wi-Fi module. Two common scenarios:

6.1 AP mode (direct connection to the command station)

The phone/tablet joins the RAILROAD network; in the RailBOX app enter IP 192.168.4.111. Some mobile devices may drop the connection while looking for Internet — §6.2 is preferable in that case.

Wi-Fi configuration page (browser): after joining RAILROAD, open http://192.168.4.111.

6.2 Home / club network (recommended for BigFred)

1. Connect a PC to the command station's AP (RAILROAD / 12345678).
2. Open http://192.168.4.111.
3. Enter your home network SSID and password; submit the form.
4. When connected, the Status field should show Connected, and IP — the address assigned by the router.

Important: the home-network IP is DHCP by default and may change after a reboot. For stable BigFred integration:

• Set a DHCP reservation on the router, or
• Disable DHCP in the command station panel and set a static address.

BigFred docs and examples often use 192.168.0.111 (e.g. example.yaml, default in config.go) — this is a workshop convention, not the factory AP address. Record the actual IP in the club runbook after configuration.

6.3 Shared LAN — parallel services

When the RB1110 and the BigFred host (e.g. Raspberry Pi) are on the same IP network:

Ports 5560, 5550, and 12090 were confirmed by RailBOX on Modelarstwo.info (Oct 2025). All four services are reachable over Wi-Fi once the command station is on the home/club LAN — no USB or serial bridge required.

Do not confuse port 5550 with XpressNet over TCP. A forum user reported connection timeouts when pointing iTrain at host:5550 expecting XpressNet; RailBOX clarified that 5550 is LenzLAN and recommends Z21 (UDP 21105) for PC integration instead. XpressNet remains on the dedicated XpressNet connector (wired handhelds).

BigFred requires stable UDP to port 21105 (Z21). Firewall and VLAN rules must allow Pi → RB1110:21105/udp.

For packet capture/debugging, Wireshark includes a Roco Z21 dissector (manufacturer note, same thread).

7. USB — DCC Command Interface

The command station exposes USB-C as a virtual serial port (CDC ACM). This is for PC software using Lenz LI100F / Lenz LI101 protocols (GBBKolejka, TrainController, JMRI in USB mode) — not the BigFred integration path.

7.1 USB identification (lsusb)

Device connected to the host (workshop example):

Bus 003 Device 005: ID 28e9:018a GDMicroelectronics DCC Command Interface

Interface descriptors:

Typical Linux device path: /dev/ttyACM*. The kernel cdc_acm driver handles this interface without vendor-specific drivers.

BigFred does not use this port — the dcc-bus daemon connects over Z21/UDP (or optionally LocoNet-TCP), see §8.

8. BigFred integration

8.1 Recommended: Z21 over UDP

RailBOX documents Z21® as the primary PC/tablet integration path. BigFred follows that: for the RB1110 use z21, not loconet_serial + Uhlenbrock 63120 adapter.

URI parser: pkgs/bigfred/dcc-bus/service/station/driver.go.

Example daemon invocation:

dcc-bus \
  --station-kind z21 \
  --station-uri "udp://192.168.0.111:21105" \
  --speed-steps 128 \
  …

Driver: pkgs/loco/commandstation/z21.go. Protocol: docs/bigfred/protos/z21.md.

BigFred capabilities over Z21 (RB1110):

External observation: 16-dcc-bus/09-external-state-observation.md.

8.2 Alternative: LocoNet over TCP (best-effort)

The RB1110 advertises LocoNet®-TCP/IP. BigFred has a loconet_tcp driver (LocoNetOverTcp — SEND / RECEIVE lines):

The official RailBOX PDF does not list the TCP port; 5560 comes from the manufacturer's forum post (Oct 2025). Requires firmware ≥ 8.0. The loconet_tcp + RB1110 combination is not officially supported in the BigFred runbook — see 07-z21-command-stations.md §7.5.

BigFred loconet_serial / loconet_tcp limits (F0–F8, no CV) — loconet.go — are another reason to prefer Z21.

8.3 What not to use with BigFred

The LocoNet RJ12 port remains for FRED and wired Piko SmartControl handhelds and feedback modules — in parallel with BigFred on Z21.

8.4 Handheld compatibility (forum reports)

For PC/throttle-hub use, RailBOX explicitly steers developers toward Z21 over Wi-Fi, not XpressNet or LenzLAN — aligned with BigFred's z21 driver.

9. BigFred setup (summary)

1. Network: RB1110 on the same LAN as the Pi; fixed IP (e.g. 192.168.0.111).
2. Admin → Command stations: create an entry, e.g. RB1110 (Z21), kind z21, URI udp://192.168.0.111:21105, speed steps 128.
3. Layout: attach the command station to a layout (POST /api/v1/layouts/{id}/command-stations).
4. Supervisord starts dcc-bus-<layout>-<station> — see 16-dcc-bus/02-process-model-and-cli.md.
5. Driver: in the throttle, pick the command station from the layout list.

One writer per command station: a concurrent RailBOX mobile app or another Z21 client may compete for slots — a typical protocol constraint, not a BigFred bug.

10. Bring-up checklist

• [ ] PSU 12–19 V / ≥3.4 A; DCC ground correctly wired to TRACK.
• [ ] RB1110 on the home network; ping 192.168.0.111 (or actual IP) from the Pi.
• [ ] UDP 21105 open (no firewall block / VLAN isolation).
• [ ] BigFred catalogue entry: z21, URI udp://…:21105.
• [ ] dcc-bus log: z21 command station: UDP socket open.
• [ ] Driver session: setSpeed moves a loco on the layout.
• [ ] LocoNet handheld change visible in the UI (Z21 broadcast).
• [ ] Second browser session on another DCC address.

Common issues: wrong IP, DHCP changed the address, firewall blocking UDP 21105, command station Wi-Fi sleep, another app holding the Z21 session.

11. Related documents

Back to the command stations index.