3 Terms and definitions

This clause defines only the words EIS uses in a sense a reader could not guess. Module, enclosure, bus board, power supply, cable, rail, rail insert, and mounting screw have their usual Eurorack meaning; chapters 5 to 9 say what EIS requires of each.

product type and role

A product type is what a requirement applies to: module, enclosure, bus board, power supply, or cable. A role is what a product does and publishes. A product's product type names its main role; whatever is built in plays its own role and owes that role's requirements, so a case with a built-in supply and bus board plays enclosure, power supply, and bus board (4.1).

Core

Core is the part of EIS every product meets, Part 2; it is never claimed. The optional interfaces of Part 3 apply only to a product that has them.

claim line, claim file, and EIS mark

The claim line is a product's conformance claim in one line, such as EIS draft, module: the edition, and the product type and every other role (4.2). The claim file, eis-claim.yaml, holds the claim and the figures the product publishes, and lists the product's power entries, outlets, and video sync ports (4.2). The EIS mark is the claim line drawn as a nameplate for a label, panel, or board (4.2).

port and port list

A port is one jack or connector on a product. The port list is the part of a product's documentation that gives, for every port, its signal class or unclassified, its range when that is not the class default, and, for a port that generates or locks to video sync, the formats it supports, and for a video sync port its mode (SIG-001, VID-001). For a bus board or an enclosure, the port list is the video_75 block of its claim file. It is published in the manual or in the claim file.

signal class and range

A signal class is a named set of level and impedance limits for a port, such as CV (7.2), AUDIO (7.2), or VIDEO (7.3). A range is the full-scale swing a port is built for, such as B10 (−10 to +10 V) or U1 (0 to +1 V). Each class lists the ranges it takes and its default.

patch jack

A 3.5 mm mono socket on a module's front panel that takes a patch cable from another module and carries a class of 7.2 or 7.3, or is unclassified. A 3.5 mm TRS socket for MIDI, headphones, or a stereo pair is a port but not a patch jack; EIS recommends that it survive a mono patch plug all the same (7.1).

class ceiling and damage limit

The levels of a signal class:

• nominal: the level an output puts on the port, such as ±5 V for audio;
• full scale: the swing the port's range allows, ±10 V at B10;
• thresholds: the levels a gate, trigger, or clock input reads;
• class ceiling: the largest signal still in class; an output that claims the class does not exceed it;
• damage limit: the level an input withstands indefinitely. On every patch input it is ±12 V (SIG-002), whatever the class ceiling: a VIDEO input has a +1.2 V class ceiling and a ±12 V damage limit.

Line level, in 8.2, is the level that a coaxial signal's own standard sets at a terminated input. It is a different quantity from the line levels of external audio in Annex C.

VIDEO path, bandwidth, and bandwidth mark

A VIDEO path is what lies between a VIDEO input jack and an output jack of one module: linear, shaped, variable, or a generator (7.3). Its bandwidth is the −3 dB frequency relative to 100 kHz, measured as 7.3 states, from a 75 Ω source into 100 kΩ in parallel with 30 pF. A bandwidth mark writes that figure as BW and the whole megahertz, BW35. A format's picture bandwidth is the luma bandwidth its publication specifies (8.3).

cover, mounting face, throat, seat, and D

The parts of a rail section:

• cover: the amount of panel face the rail hides; it limits the board clearance (5.2.2);
• mounting face: the face the panel bears on;
• throat: the opening in front of the insert that the screw passes through;
• seat: the depth of the insert's front face behind the mounting face;
• D: the depth behind the mounting face at which metal closes the cavity a screw tip enters.

Seat and D set the screw length window (5.3).

video sync

Video sync is the horizontal and vertical timing of a video signal: black burst, or bi-level or tri-level video sync, of one 8.3 format, alone or within a composite picture. A row distributes it so that its video modules lock their timing to one source. It travels behind the panel on the 75 Ω coaxial interface (8.2), from a COAX-OUT to each COAX-IN, and never on a patch jack (7.1). EIS always writes video sync in full.

A video sync port has one of three modes:

• COAX-IN takes video sync;
• COAX-OUT gives video sync the product generates;
• COAX-THRU, marked THRU, passes the COAX-IN's video sync on, either buffered, driving one input, or looped, bridged to the input on one line with a termination switch marked TERM.

A video sync distributor is any product, usually a bus board, with buffered COAX-THRU ports beside its COAX-IN. The tree is the star of 75 Ω cables from its THRU ports to each module's COAX-IN.

power interface, power entry, and outlet

A power interface is a set of rails with its own connectors, distribution, and limits: PWR-BUS, the bus (+12 V, −12 V, optional +5 V), or PWR-DC12, 12 V DC (6.1). In a designator the word names the topology and the number the rail voltage: BUS is the Eurorack bus, DC12 a single 12 V DC rail. PWR-BUS is Core and PWR-DC12 an optional interface; their rules apply to a product that has an entry or an outlet of them.

• A power entry is where a power interface enters a product: a module's power header, or a DC entry.
• An outlet is where a power supply or a distribution product delivers it: a supply's output terminals, a bus board's headers, a product's PWR-DC12 outlets.

0 V and protective earth

0 V is the reference every rail and signal of a row is measured from: the 0 V pins of the power header, the sleeve of a patch jack, the shell of a coaxial jack, and the −V of a DC rail. Protective earth is the mains safety conductor. They are different conductors, joined at one point in a system, its chassis tie at the power entry, which a supply (GND-003) or a case DC entry (DC-014) publishes (6.3).

DC entry and DC rail

A DC entry is the inlet where nominal 12 V DC from an external adapter enters a product: a center-positive barrel (DC-BAR21 or DC-BAR25) or a multi-pin connector (DC-VH2 from a DC distribution product, or, above 10 A, DC-DIN4, DC-MF6, or DC-MF8). The DC rail is the 12 V DC that a DC entry feeds, one +V and −V pair, carried to modules directly or through a DC distribution product on DC-BAR21 or DC-VH2; each module filters or regulates it locally. The DC rail is not the ±12 V bus (8.1).

video timing format

A named raster, such as 525i59.94 or 1080p30, with its line count, sample clock, and video sync structure tabulated in data/video_timings.json. 8.3 lists the formats EIS defines.

provenance

The origin of a requirement's value, recorded per row in data/requirements.json (1.4):

• quoted from a dated external publication;
• inherited from a Doepfer A-100 convention, Hinton Instruments' power distribution, or the Intellijel 1U format, with the page and the date it was retrieved;
• measured on a named vendor part;
• calculated from other EIS requirements, which the record names;
• eis: set by EIS itself.

Requirement language

EIS does not use the RFC 2119 MUST, SHOULD, or MAY, and has no "should" level.

Every shall statement in a normative clause carries a requirement identifier, written in prose without the EIS- prefix (PANEL-009), and the requirements register lists it. A may statement need not carry one; a recommendation carries none. Text in a normative clause that uses none of these words is informative: it explains, gives an example, or restates a requirement made elsewhere. Sections, tables, and annexes marked informative impose no requirements. The register and the data models are the specification; where a clause differs from them, the clause is in error (4.4).