The TASCAM AES/EBU digital DB-25 connector uses a 25-pin D-subminiature (DB-25) to carry eight AES3 digital audio streams — four receive pairs (Digital In, channels 1–8) and four transmit pairs (Digital Out, channels 1–8) — on a single connector, accommodating 16 audio channels bidirectionally. The format was developed by TASCAM for the DA-88 DTRS tape recorder (introduced 1992) and became the dominant professional digital I/O wiring convention before being ratified as AES59-2012 by the Audio Engineering Society. Each AES3 pair occupies three pins (Hot, Cold, and an independent Shield/Ground); pin 13 is always unconnected. Major adopters include Avid (Pro Tools HD 192 I/O), MOTU, SSL, RME, Metric Halo, Dangerous Audio, and SPL.
TASCAM Pinout
| | DB-25 Pin Number | | Channel | |——————–|——————-| | 1 | Digital Out 7/8 + | | 2 | Ground | | 3 | Digital Out 5/6 - | | 4 | Digital Out 3/4 + | | 5 | Ground | | 6 | Digital Out 1/2 - | | 7 | Digital In 7/8 + | | 8 | Ground | | 9 | Digital In 5/6 - | | 10 | Digital In 3/4 + | | 11 | Ground | | 12 | Digital In 1/2 - | | 13 | No Connect | | 14 | Digital Out 7/8 - | | 15 | Digital Out 5/6 + | | 16 | Ground | | 17 | Digital Out 3/4 - | | 18 | Digital Out 1/2 + | | 19 | Ground | | 20 | Digital In 7/8 - | | 21 | Digital In 5/6 + | | 22 | Ground | | 23 | Digital In 3/4 - | | 24 | Digital In 1/2 + | | 25 | Ground |
Notes
- The equipment chassis carries a female DB-25F connector; cables use a male DB-25M plug at both ends (AES59-2012 convention).
- Jackscrews are 4/40 UNC thread; metric M3 hardware is not compatible with the standard.
- The combined I/O arrangement places Digital In (AES3 receive) on the pin positions corresponding to analogue channels 1–4, and Digital Out (AES3 transmit) on the positions corresponding to analogue channels 5–8.
- Analogue and AES/EBU digital DB-25 cables use different internal wiring and are not interchangeable, even though the shell and pinout positions share the same numbering convention.
- Yamaha equipment uses a physically identical but electrically incompatible DB-25 wiring; cross-manufacturer connections require a pin-swapped adaptor snake.
- AES3 supports dual-wire (double-speed) mode for sample rates up to 192 kHz when the host interface implements it.
Signals
- Digital In 1/2 + — AES3 receive, channels 1–2, positive (Hot); pin 24
- Digital In 1/2 - — AES3 receive, channels 1–2, negative (Cold); pin 12
- Digital In 3/4 + — AES3 receive, channels 3–4, positive (Hot); pin 10
- Digital In 3/4 - — AES3 receive, channels 3–4, negative (Cold); pin 23
- Digital In 5/6 + — AES3 receive, channels 5–6, positive (Hot); pin 21
- Digital In 5/6 - — AES3 receive, channels 5–6, negative (Cold); pin 9
- Digital In 7/8 + — AES3 receive, channels 7–8, positive (Hot); pin 7
- Digital In 7/8 - — AES3 receive, channels 7–8, negative (Cold); pin 20
- Digital Out 1/2 + — AES3 transmit, channels 1–2, positive (Hot); pin 18
- Digital Out 1/2 - — AES3 transmit, channels 1–2, negative (Cold); pin 6
- Digital Out 3/4 + — AES3 transmit, channels 3–4, positive (Hot); pin 4
- Digital Out 3/4 - — AES3 transmit, channels 3–4, negative (Cold); pin 17
- Digital Out 5/6 + — AES3 transmit, channels 5–6, positive (Hot); pin 15
- Digital Out 5/6 - — AES3 transmit, channels 5–6, negative (Cold); pin 3
- Digital Out 7/8 + — AES3 transmit, channels 7–8, positive (Hot); pin 1
- Digital Out 7/8 - — AES3 transmit, channels 7–8, negative (Cold); pin 14
- Ground — independent shield/earth connection for each signal pair; pins 2, 5, 8, 11, 16, 19, 22, 25
- No Connect — pin 13; reserved and unused in all AES59 configurations
References
- 192 I/O Guide (Digidesign 192 I/O 16-Channel Audio Interface) — Digidesign / Avid Technology
- DA-98HR Technical Documentation — TASCAM (TEAC Corporation)
- AES59-2012 (r2023): AES standard for professional audio — Audio application of 25-way D-type connectors in balanced circuits. Audio Engineering Society, 2012.