RM 4200D

The faders on RM420-020MW and RM420-029MW modules require calibration, which DHD performs during manufacturing — recalibration is especially necessary when swapping from plastic to metal faders (Penny & Giles PGFM8100 to PGFM3200). The process is done via Toolbox4's maintenance window using a CAN Block command that includes the processor module's serial number converted to hexadecimal (e.g. decimal 12783 → hex 31EF → command 01ED31EF,5).

While colored fader knobs can generally be swapped on RM4200D fader modules, this is not possible for modules with motorized faders. Motorized faders require conductive knobs to detect touch, and these are currently only available in silver.

Upgrading an RM4200D to the Series 52 firmware generation requires replacing the RM420-850 Communication Controller with an RM420-852 or RM420-853 module. If the console includes a TFT display, the wiring to the controller must be redone according to the new connection scheme — detailed wiring information is available in the 52/MX Manual and Installation Guide.

The peak program meter behavior in DHD systems is configured via the "Level Detection" settings in Toolbox4/Toolbox5. To emulate an analog PPM (DIN 45406 / IEC 268-10 Type I), set Attack to 2ms and Release to 0.7s; for a digital PPM, use Attack 0ms (or 1ms if integration time is needed) and the same Release of 0.7s.

The DHD Communication Server (DHDCS) manages all communication between DHD devices and PC applications, and is bundled with software like Toolbox5, Toolbox4, and several RM420 tools — automatically extracting and launching when needed. For correct operation, the logged-in Windows user requires administrative rights; non-admin setups require a manual one-time DHDCS.exe binding to a dedicated folder with full user access rights granted. Running DHDCS without admin rights is possible since version 1.90.13 but not recommended, as it disables Ping messaging and can cause TCP/IP connection issues.

Not all fiber-optic cables are compatible with DHD MADI modules — suitability depends on the specific module. The linked PDF lists all compatible fiber-optic cable types and maps them to the individual MADI modules they can be used with.

The DHDCS intentionally does not save filter settings between sessions — after every restart, all filters are reset to deselected. This is a deliberate security measure to prevent important error messages from being permanently suppressed.

In the DHD Communication Server, logging for individual devices can be toggled via right-click context menu, with multiple Log Levels available depending on the DHDCS version. Note that these Log Level options are greyed out and unavailable for RM4200D devices (Toolbox4 firmware), while full Log Level support is provided for 52/RM4200D (Toolbox5), 52/MX, and 52/XR systems.

The RM420-015B replaces the RM420-015 and is automatically substituted in all orders, with the only difference being its power supply — it uses Power over Ethernet (PSA16U480POE) instead of a 48V socket. Ordering a 52-4015A, 52-3015A, and PSA16U480POE together yields the equivalent hardware kit.

DHD software such as Toolbox4/4.5 may not run correctly on Windows 7 without adjustments — setting the compatibility mode to Windows XP (Service Pack 3) and enabling "Run as administrator" in the program's properties typically resolves this. As a fallback, Windows XP Mode (available for Windows 7 Professional and Ultimate) may also be used.