Shure SLX-D Wireless

Shure SLX-D digital wireless receivers (the single-channel SLXD4 and the dual SLXD4D) are controlled over Shure's Command Strings protocol: plain ASCII in < ... > frames on TCP port 2202, the same protocol the Shure Microflex / IntelliMix driver uses. This driver connects to one receiver and reports what each channel's transmitter is doing: battery, transmitter type, channel name, gain and frequency. It raises an alarm when a mic's battery runs low.

The receiver has no mute

SLX-D has no mute command. To mute a wireless mic from GEM, mute the DSP or network-interface input the receiver feeds, for example a P300 or ANI4IN channel through the Shure Microflex / IntelliMix driver.

Prerequisites

• The receiver on the control network with a static IP or DHCP reservation.
• TCP port 2202 reachable from GEM. There is no password. Only a few control connections are allowed at once, so close Wireless Workbench or any other control session if GEM cannot connect.

Setup

1. Add a device with the Shure SLX-D Wireless driver, under an AV subsystem, and set Receiver IP. Leave the port on 2202.
2. Add a zone for each channel, bound to the device, with its address set to the channel number: 1, plus 2 on an SLXD4D.
3. Save and reload the device. On connect GEM reads everything with GET 0 ALL. After that the receiver reports every change as it happens, and GEM re-reads everything on the poll interval (30 seconds by default).

What each channel zone shows

Attribute	Meaning
battery_bars	Transmitter battery, 0–5 bars. Not written while the receiver reports it as unknown.
battery_minutes	Runtime left, in minutes. Only Shure rechargeable batteries report this, and only once the transmitter has finished calculating.
battery_state	ok, low, calculating, warning (battery communication warning), unknown, or off (no transmitter heard).
tx_model	slxd1 (bodypack), slxd2 (handheld), or none.
transmitter_on	Whether the receiver hears a transmitter on this channel.
channel_name	The channel name set on the receiver.
gain_db	Receiver audio gain, −18 to +42 dB.
frequency_mhz	Operating frequency.
group_channel	Group and channel, e.g. 1,1, or --,-- for a manually set frequency.
audio_output_level	mic or line, from the receiver's output switch.

The device itself gets model, device_id_label, rf_band, firmware_version and lock_status. Each value is written only when it changes, so the poll doesn't fill attribute history.

Battery and the low-battery alarm

A channel counts as low when its transmitter reports low_battery_bars bars or fewer (default 1), or low_battery_minutes minutes or less of runtime (default 60). Both thresholds are device attributes. The bars test works with AA batteries; the minutes test only applies to Shure rechargeables.

When a channel goes low, GEM raises the Wireless Mic Battery Low system alarm (medium severity) on that channel's zone, once per low spell. It clears when the battery reads above the thresholds again, or when the transmitter is switched off. While runtime still reads calculating, GEM doesn't decide either way.

Commands

Command	Arguments	Action
refresh	—	Re-read every receiver and channel property.
gain	address, gain_db	Set a channel's audio gain, −18 to +42 dB in whole dB. Values outside are clamped.
gain_up / gain_down	address, step_db	Step a channel's gain (default 1 dB). The receiver stops at its own limits.
get_gain	address	Query a channel's gain.
get_battery	address	Query a channel's battery bars and runtime.
get_channel_name	address	Query a channel's name.
flash_on	address (optional)	Flash the receiver to identify it, or one channel when an address is given.
get_device_id / get_model	—	Query the receiver's id / model.

The receiver's gain is the mic's output trim. Set it once during commissioning and leave room level to the DSP. Commands that take a channel refuse anything other than 1 or 2.

Known limitations

• No mute. See the warning above.
• No metering. Audio levels and RF signal strength (SAMPLE, METER_RATE) are not read, so they never flood attribute history. Use Wireless Workbench for RF work.
• No frequency or name changes. Frequency, group/channel and channel name are read-only here. Set them on the receiver or in Wireless Workbench.

Troubleshooting

Symptom	Check
No response / connection refused	Confirm the receiver IP and that port 2202 is reachable. Close any other control session holding a connection.
Zone never updates	The zone address must be the channel number, 1 or 2. An SLXD4 has only channel 1.
battery_state stays unknown with a transmitter on	Runtime is only reported for Shure rechargeables. With AA cells, bars still report, and the alarm uses bars.
Alarm raised for a mic that is fine	Lower low_battery_bars or low_battery_minutes on the device.

Related

• Shure Microflex / IntelliMix — mute and level for the DSP input the receiver feeds.
• Alarms — notification and escalation for the low-battery alarm.