m908 User Manual, Rev. G
3. Option I/O slot (Dante , Digilink, and MADI options): The Option I/O module can receive and
transmit 32 channels of PCM audio.
4. Analog balanced input ADC (optional): There are slots for two optional 8 channel ADC
modules with DB25 input connectors. The ADC modules plug in to the main digital pcb. Two
ADC modules can be used for a total of 16 channels. The ADC in position 1 is also connected
to the stereo balanced XLR and unbalanced phono jacks so that it can be used for monitoring
stereo sources on channels 1-2. Note that when an input uses the stereo connections, channels
1-2 on the DB25 connector are not available for assignment.
5. Stereo Input analog unbalanced RCA Phono: Present if an ADC option module is installed. Can
be switched to Phono level if the RIAA Phonograph Preamplifier module is installed.
6. Stereo Input balanced analog XLR: Present if an ADC option module is installed.
7. Control Room 3 Output balanced analog XLR: Analog output signals sourced from DAC
channels 1-2.
8. Talkback output balanced analog XLR: Talback signal sourced from ACU or RCU Mic. Can be
configured to be momentary while talkback is active or continuously on.
9. Talkback mic input balanced XLR: Balanced microphone level input with available 48V
phantom power. The talkback signal is fed to an ADC and sent to the DSP section and can also
sent to the Talkback output XLR connector when talkback is active.
10. External Talkback switch jack 1/4" TRS: Wiring a normally open switch to this jack will allow
for another talkback control. The Ring of this connector carries current limited 5V for
powering a tally LED. See
11. Ethernet Control Port RJ45: Reserved for future use.
12. RCU serial control DB15: Connect to RCU with supplied DB15 cable.
13. USB Host USB-A: USB host connector for system firmware update.
14. AES3 Input XLR: Stereo AES digital input. Supports sample rates from 44.1kHz-192kHz.
15. SPDIF Input RCA Phono
16. ADAT/TOSLINK x 2 Optical: Optical receivers for ADAT or TOSLINK. Supports SMUX for
8ch 96kHz operation.
17. USB Audio I/O USB-B: The USB Audio Class 2 compliant interface allows for monitoring up
to 24 channels of PCM audio at 48kHz/24bit and 8 channels of PCM audio at 192kHz/24bit.
18. Word Clock IN BNC 75Ω or 47kΩ (setup menu selected): External clock input.
19. Word Clock OUT / THROUGH BNC 75Ω: Output clock signal can be a buffered copy of the
incoming word clock or can be from the internal word clock.
20. Control Room 1 output balanced analog DB25 (Tascam pinout): Analog output signals sourced
from DAC channels 1-8.
21. Control Room 2 output balanced analog DB25 (Tascam pinout): Analog output signals sourced
from DAC channels 1-8
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