7.1 Signals

How a module declares what travels on each port, and the rules every patch jack follows whatever it carries.

Clause Covers
7.2 Patch signal classes Audio, control CV, pitch CV, gate, trigger, clock, and video on patch jacks, and their ranges
7.3 Video timing The formats a video reference port lists
7.4 Video on 75 Ω coaxial jacks (VID-75) The 75 Ω coaxial interface: the video reference ports VID-REF-IN, VID-REF-OUT, VID-REF-PASSTHRU, VID-REF-LOOPTHRU, the reference tree, and the coaxial cable
Annex I Informative names for ports that are not patch jacks

Port list

A module shall publish a port list naming, for every port, its signal class or unclassified (SIG-001). A module with no ports publishes an empty list. A port's direction is in, out, or in_out for one that is both, such as a loop-through pair or a bidirectional expander link. Beside the class, the port list names the range a port claims when it is not the class default (7.2), and a port that generates or locks to a video reference lists its formats (7.3). The port list belongs in the manual, on the product page, or in a claim file.

A port that claims a class meets that class's limits in 7.2. A port that is neither a patch jack nor a video reference port, such as a coaxial picture jack, line audio, or MIDI, is listed as unclassified or by a name from Annex I; EIS places no requirement on it. EIS recommends labelling each port with its class, on the panel or in the manual.

Patch safety

These requirements apply to every patch jack on a module, whatever its class:

The ±12 V is the rails' nominal figure, applied from a source of 1 kΩ or less; a supply's 10 % start-up overshoot (SUP-006) is a rail figure, and no conforming output drives a tip beyond ±12 V while its rails are anywhere inside the supply's limits. EIS recommends that a patch input withstand ±15 V, the rails of the ±15 V systems a patch cable can reach through an adapter, and that every other 3.5 mm socket on the panel, a TRS MIDI, headphone, or stereo port, withstand ±12 V on its tip and a short from tip to sleeve, since a mono patch plug fits it.

EIS recommends that every patch jack, and every RCA, BNC, or SMA jack, have its sleeve or shell insulated from the panel metal, so that no signal return runs through the panel and the case.

EIS · The patch interface and its limits Audio, CV, pitch, gate, trigger, and clock output about 1 kΩ tip patch cable tip 100 kΩ input Video, MOD-VIDEO output 75 Ω ±5 % (SIG-010) tip patch cable tip 100 kΩ ±10 % (SIG-009) input On every patch jack An input withstands ±12 V indefinitely (SIG-002). An output survives a short to 0 V or to another output (SIG-003). An output never drives the tip beyond ±12 V (SIG-004). Insulated jacks, recommended panel jack insulating bush EIS recommends insulating every patch, RCA, BNC, and SMA jack from the panel. 75 Ω into 100 kΩ arrives at almost unity gain. A MOD-VIDEO output has no other source impedance (SIG-010), so every video output and input in a system match.

Video reference in a row

Video modules in a row share one video reference, and a module takes it behind the panel at a VID-REF-IN port, a rear 75 Ω coaxial jack under 7.4: fed from the VID-REF-OUT of a video reference generator, from the VID-REF-PASSTHRU of the module before it, or from a distributor, usually a bus board, whose VID-REF-PASSTHRU ports fan one reference out to one VID-REF-IN per module. A module claims each reference port it has by kind, VID-REF-IN, VID-REF-OUT, VID-REF-PASSTHRU, or VID-REF-LOOPTHRU. A patch jack shall carry patched signals only: a module shall neither take nor give its video reference at a patch jack, and no patch jack shall list a format of clause 7.3 (SIG-015). The reference is system configuration, wired once behind the panel, so patching never changes a module's timing. Informative Annex M describes the choices. Power for a video distribution product is ordinary module or case wiring, from the bus or a DC entry, and is not part of the feature.