# Connecting to a Macʼs USB Port

Using the Type A - Type B USB cable included in the box, connect Symphony I/O's USB port to an Apple Intel Mac USB port. If the included USB cable isn't used, ensure that the cable used is certified for USB 2.0 operation.

| ##  | ## Symphony Audio Interface Mode

> When Audio Interface Mode is set to Symphony PCI, the USB port is used for updating firmware only. See Updating Firmware for details.

| ##  | ## Pro Tools HD Audio Interface Mode

- When Audio Interface Mode is set to Pro Tools HD, a USB connection between Symphony I/O and an Intel Mac provides the link between Apogee Maestro software and Symphony I/O, in order to make calibration, meter configuration, digital format and other settings.

- Symphony I/O's clock source and sample rate are set from Pro Tools software, and don't require the USB connection.

- The USB connection is only required to make Maestro settings, and may be removed once settings are complete.

- Note that the audio and USB connections don't have to be made to the same computer, allowing Symphony I/O to be connected to Pro Tools HD cards installed in Apple Mac G5 or Windows computers while running Maestro on an Apple Intel Mac.

| ##  | ## Standalone Interface Mode

- When Audio Interface Mode is set to Standalone, a USB connection between Symphony I/O and an Intel Mac provides the link between Apogee Maestro software and Symphony I/O, in order to make calibration, meter configuration, digital format and other settings.

- Symphony I/O's clock source and sample rate may be set using the front panel encoders, and don't require the USB connection.

- The USB connection is only required to make Maestro settings, and may be removed once settings are complete.

- Note that the audio and USB connections don't have to be made to the same computer, allowing Symphony I/O's Optical or AES I/O to be connected to an Windows computers while USB is connected to an Apple Intel Mac.

| ##  | ## USB Audio Interface Mode

- When Audio Interface Mode is set to USB Audio, a USB connection between Symphony I/O and an Intel Mac provides 16 channels of bi-directional audio at sample rates up to 96kHz, as well as the link between Apogee Maestro software and the Symphony I/O.

- Symphony I/O's clock source is fixed to Internal.

- When transmitting audio via Symphony I/O's USB connection, it's recommmended to connect directly to the Mac, avoiding the use of USB hubs.