Annex C (informative) — Port vocabulary
Annex C gives class names for ports that are not patch jacks, so that manuals and port lists (SIG-001) describe them the same way: line, instrument, microphone, and headphone audio, digital audio, analog and digital video, MIDI, DMX512, the DIN clock interface, word clock, an expander link, and the ILDA laser connector. Such a port does not change whether one Eurorack product fits or works with another, so EIS places no requirement on it.
- Port list. A port of this annex is listed by its class name or as
unclassified; either satisfies SIG-001. - Not a patch class. A class of this annex names a port; a module lists it beside its patch jacks (7.2).
- Patch jacks. A port on a 3.5 mm mono patch jack is a patch jack whatever it carries, and the patch-safety rules of 7.1 apply to it. EIS recommends that a 3.5 mm TRS port survive a mono patch plug as well.
- Figures. Levels and impedances are the usual industry figures, for orientation; the Nominal column names the level or the governing document, whichever defines the port. Where a published standard governs a port, the product cites that standard directly; EIS applies none of them by reference.
C.1 External audio
Balanced ports are pin 2 or tip hot (AES14, IEC 60268-12). A microphone input that offers phantom power states it beside the port, since P48 per IEC 61938 can damage a line output patched into it. A headphone output states the load its level figure assumes; headphones run from 16 Ω to 600 Ω. The digital audio ports carry no EIS level; the classes name S/PDIF (IEC 60958-3), AES3, ADAT, and USB Audio Class so that a port list can say which.
| Class | Connector | Coupling | Nominal | Class ceiling | Source Z | Load Z |
|---|---|---|---|---|---|---|
| LINE-BAL | 6.35 mm TRS or XLR | AC | +4 dBu (1.228 V RMS); pin 2 or tip hot (AES14, IEC 60268-12) | +24 dBu | 200 Ω | 10 kΩ |
| LINE-UNBAL | 6.35 mm TS, RCA, or 3.5 mm TRS stereo pair | AC | −10 dBV (316 mV RMS); tip left, ring right on a TRS pair | +8 dBV | 600 Ω | 10 kΩ |
| INST | 6.35 mm TS | AC | Instrument level; passive pickup source 5 kΩ to 20 kΩ | +12 dBu | — | 1 MΩ |
| MIC | XLR | AC | −60 to −40 dBu typical; pin 2 hot; phantom power, when offered, is P48 per IEC 61938 (48 V ± 4 V through 6.8 kΩ) and is stated beside the port | +10 dBu | 200 Ω | 2 kΩ |
| AUD-HP | 3.5 mm or 6.35 mm TRS | AC | Headphone output, tip left, ring right; level into the stated load | Per the product | 10 Ω | 32 Ω |
| DIG-SPDIF | RCA 75 Ω or TOSLINK | Digital | S/PDIF per IEC 60958-3, 0.5 V p-p into 75 Ω on RCA | Per IEC 60958-3 | 75 Ω | 75 Ω |
| DIG-AES3 | XLR 110 Ω | Digital | AES3, 2 to 7 V p-p into 110 Ω balanced | Per AES3 | 110 Ω | 110 Ω |
| DIG-ADAT | TOSLINK | Digital | ADAT Lightpipe, eight channels at 48 kHz (four at 96 kHz S/MUX) | Per the ADAT optical interface | — | — |
| DIG-USB-AUDIO | USB | Digital | USB Audio Class 1 or 2, as stated | Per the USB Audio Class | — | — |
C.2 External video
Composite and component video on 75 Ω coaxial jacks on the front are external ports like the audio ports above. A port list names each by its class (VID-CVBS, VID-YPBPR, VID-RGBS, VID-RGSB, VID-RGBHV) with the formats it carries. EIS recommends that such a port take the COAX-IN termination or the COAX-OUT back-termination of 8.2. The video sync ports behind the panel belong to 8.2 and are listed by mode.
- Levels. Y with video sync is 1 V p-p whether the video sync is bi-level (−300 mV tip) or tri-level (±300 mV); Pb and Pr are 700 mV p-p.
- RGB. Three connector contracts, of which a product names the one it has: separate composite video sync, four components (VID-RGBS); video sync on green, three components (VID-RGSB); separate horizontal and vertical video sync, five components on five coaxial jacks or a D-sub 15 (VID-RGBHV).
- Placement. Each is a front or wall port; no BNC jack is inside the case (SIG-017).
- HDMI. The HDMI specification is available to adopters only, so a product states its HDMI version in its own documentation.
| Class | Connector | Coupling | Nominal | Class ceiling | Source Z | Load Z |
|---|---|---|---|---|---|---|
| VID-CVBS | RCA, BNC, or SMA, 75 Ω | DC | Composite video, 1 V p-p into 75 Ω: 525-line per SMPTE ST 170, 625-line per ITU-R BT.1700 | Per the composite standard | 75 Ω | 75 Ω |
| VID-YPBPR | 3 × RCA, BNC, or SMA, 75 Ω | DC | Component video into 75 Ω: Y 700 mV video plus video sync, 1 V p-p with bi-level video sync (EIA-770.1 and 770.2) or tri-level ±300 mV (EIA-770.3, SMPTE ST 274 and ST 296); Pb and Pr 700 mV p-p | Per the component standard | 75 Ω | 75 Ω |
| VID-SVIDEO | 4-pin mini-DIN per IEC 60933-5 | DC | Y 1 V p-p with video sync, C 286 mV p-p burst (525-line, ST 170) or 300 mV (625-line, BT.1700) | Per SMPTE ST 170 or ITU-R BT.1700 | 75 Ω | 75 Ω |
| VID-RGBS | 4 × RCA, BNC, or SMA, 75 Ω (R, G, B, composite video sync) | DC | R, G, B 700 mV p-p into 75 Ω; separate composite video sync 300 mV (video) or TTL, stated by the product | Per EIA-770 or the product's statement | 75 Ω | 75 Ω |
| VID-RGBHV | 5 × RCA, BNC, or SMA, 75 Ω (R, G, B, H, V), or D-sub 15 (VGA) | DC | R, G, B 700 mV p-p into 75 Ω; H and V video sync TTL on separate conductors; timing per the format, VESA DMT for a VGA mode | Per EIA-770 or VESA | 75 Ω | 75 Ω |
| VID-RGSB | 3 × RCA, BNC, or SMA, 75 Ω | DC | R, G, B 700 mV p-p into 75 Ω with video sync on green, G 1 V p-p with bi-level or tri-level video sync | Per EIA-770 | 75 Ω | 75 Ω |
| VID-HDMI | HDMI Type A | Digital | HDMI Type A connector; version per product documentation | Per HDMI specification | — | — |
| VID-SDI | BNC 75 Ω | Digital | SD-SDI, HD-SDI, 3G-SDI, 6G-SDI, or 12G-SDI per SMPTE | Per SMPTE ST 259, ST 292, ST 424, ST 2081, ST 2082 | 75 Ω | 75 Ω |
C.3 Control and data
The table gives each connector's pinout and level. MIDI TRS Type B swaps the tip and ring of Type A, and the two do not interwork; EIS recommends that a product with Type B wiring say so next to the jack. The DIN clock interface runs at 24 pulses per quarter note (Roland) or 48 (Korg), and the product states which. A word clock input states whether it terminates or loops through. An XLR-3 lighting port is common but is not DMX512-A. LINK names an expander or chaining header between products of one maker, which EIS does not define.
| Class | Connector | Coupling | Nominal | Class ceiling | Source Z | Load Z |
|---|---|---|---|---|---|---|
| MIDI-DIN | 5-pin DIN | Digital | MIDI 1.0 current loop (5 V or the 3.3 V option of CA-033); an output and a thru are both MIDI-DIN, stated by the product | Per MIDI 1.0 | — | — |
| MIDI-TRS-A | 3.5 mm TRS Type A | Digital | MIDI Association RP-054 Type A: tip to DIN pin 5, ring to pin 4, sleeve to pin 2 | Per MIDI Association RP-054 | — | — |
| MIDI-TRS-B | 3.5 mm TRS Type B | Digital | MIDI Association RP-054 Type B: tip to DIN pin 4, ring to pin 5, sleeve to pin 2 | Per MIDI Association RP-054 | — | — |
| DMX512 | XLR-5 (E1.11); RJ45 per ANSI E1.27-2 | Digital | ANSI E1.11 DMX512-A; an XLR-3 port is not DMX512-A and is listed as unclassified | Per ANSI E1.11 | — | — |
| SYNC-DIN | 5-pin DIN | DC | the DIN clock interface, 24 or 48 PPQN as stated: pin 1 start/stop, pin 3 clock, pin 2 0 V, 0/+5 V TTL | TTL (5 V) | — | — |
| CLK-WORD | BNC 75 Ω | DC | Word clock, as AES11 Annex B (informative) describes it: a square wave at the sample rate, TTL at the source, about 2.5 V at a 75 Ω termination; an input states whether it terminates or loops through | TTL (5 V) | 75 Ω | 75 Ω |
| LINK | A board-to-board or expander header, as the product documents | Digital or analog, as documented | An expander or chaining connection between products of one maker; outside EIS | Per the product | — | — |
C.4 ILDA laser
Laser safety and interlock behavior follow the ILDA document and the applicable laser safety regulations, not EIS.
| Class | Connector | Coupling | Nominal | Class ceiling |
|---|---|---|---|---|
| ILDA-DB25 | DB-25 | Analog | ILDA ISP-DB25: X and Y differential pairs ±5 V per leg (±10 V differential), color 0 to +5 V, shutter TTL, interlock | Per ILDA ISP-DB25 |