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iMac (Mid 2011): External features, ports, and connectors

Learn about the external features, ports, and connectors on the iMac (Mid 2011) computers. All ports and connectors described in this document are located on the Input/Output (I/O) panel on the bottom-right side on the back of the computer.

Back of iMac (Mid 2011)

Note: Pictured above is the iMac (27-inch, Mid 2011) with two Thunderbolt ports. The iMac (21.5-inch, Mid 2011) has one Thunderbolt port.

Front ports of an iMac (Mid 2011)

Features

Built-in SD (Secure Digital) Card Reader

The built-in SD card slot allows the iMac (Mid 2011) to read and write data to SD media. The slot accepts cards that are Standard SD (Secure Digital) 4 MB to 4 GB, SDHC (Secure Digital High Capacity) 4 GB to 32 GB, and SDXC (Secure Digital Extended Capacity) cards of 32 GB and larger. For complete information on the card slot, see About the SD and SDXC card slot.

Built-in microphone

The internal microphone operates independently from all other audio input ports and is always available. The internal microphone supports recording at bit depths of 16, 20, or 24 bits per sample and at sample rates of 44.1 kHz, 48 kHz, or 96 kHz. Audio recorded from the microphone is presented as a stereo data stream with the same data on both the left and right channels. You can adjust the microphone gain from -16 dB to +30 dB.

Built-in FaceTime HD camera

Video chat using FaceTime for Mac or iChat over a broadband connection, take pictures using Photo Booth, or capture video through iMovie HD. The camera has an indicator light that glows when the camera is in use.

Slot-loading optical disc drive

The SuperDrive can read CD-ROM, photo CD, audio, and DVD discs. It can write to CD-R, CD-RW, DVD±R, DVD±RW, and DVD±R Double-Layer (DL) discs.

Built-in infrared (IR) receiver for Apple Remote

The infrared-based Apple Remote (sold separately) works with the built-in IR receiver for use with Front Row to access DVD Player, iPhoto, iTunes, and QuickTime Player.

I/O ports

Thuderbolt port

Thunderbolt is a revolutionary I/O technology that supports high-resolution displays and high-performance data devices through a single, compact port.

Thunderbolt digital video output

The iMac (Mid 2011) has Thunderbolt ports that support:

  • Mini DisplayPort output using a Mini DisplayPort to Mini DisplayPort cable (optional)
  • DVI output using a Mini DisplayPort to DVI Adapter (optional)
  • VGA output using a Mini DisplayPort to VGA Adapter (optional)
  • Dual-Link DVI output using Mini DisplayPort to Dual-Link DVI Adapter. Supports 30-inch Apple Cinema HD Display (optional)
  • HDMI audio and video output using a third-party Mini DisplayPort to HDMI Adapter
  • The Thunderbolt port does not accept input for Target Display Mode via a Mini DisplayPort cable.

FireWire

The iMac has one FireWire 800 port supported by an Open Host Controller Interface (OHCI) FireWire controller with a FireWire 800 PHY (Physical Layer). The FireWire 800 port supports IEEE 1394b with a maximum data rate of 800 Mbps (100 MBps). The iMac (Mid 2011) supplies 7W for the port.

The iMac (Mid 2011) computers support Target Disk Mode (TDM).

Ethernet port (10/100/1000 Base-T)

The iMac (Mid 2011) has a built in Ethernet port for 10Base-T/UTP, 100Base-TX and 1000Base-T Gigabit operation. You can connect your iMac to an Ethernet cable from a cable or DSL modem, hub, switch, or router, or to another Macintosh computer.

The connected device can be either a 10Base-T, 100Base-T or 1000Base-T device; the port automatically detects which type of device is connected. You don't need to use an Ethernet crossover cable to connect to other Ethernet devices.

The Ethernet port supports the configuration of Ethernet frames larger than 1,500 MTU (Maximum Transmission Unit).

Four USB (Universal Serial Bus) 2.0 ports

The back of the iMac (Mid 2011) has a total of four USB 2.0-compliant ports. You can connect both USB 2.0- and USB 1.1-compliant devices to these ports. The USB 2.0 ports support both low-speed, full-speed, and high-speed data transfers, up to 1.5 megabits per second (Mbit/s), 12 Mbit/s, and 480 Mbit/s respectively.

The aluminum Apple keyboard has a USB hub with two high-speed USB 2.0 ports.

All the USB ports use USB Type A connectors, which have four pins each.

Audio line input/optical digital audio input port

Line input

The analog line input operates independently from all other audio input ports and is always available. The line input supports recording at bit depths of 16, 20, or 24 bits per sample and at sample rates of 44.1 kHz, 48 kHz, or 96 kHz. Audio recorded from the line input is presented as a stereo data stream. You can adjust the line input gain from -16 dB to +30 dB.

During input of a 1 kHz, 1 VRMS (-3 dBFS) sine wave (44.1 kHz input sample rate, 24-bit sample depth, 0.0 dB input gain, no weighting) the audio line input has the following nominal specifications:

  • Jack type: 3.5 mm (1/8-inch) stereo
  • Maximum input voltage: 3 VRMS (+11.8 dBu)
  • Minimum voltage input for full scale output: 63 mVRMS (-21.5 dBu) at input gain = +30 dB
  • Input impedance: > 20 kilohm
  • Frequency response: 20 Hz to 20 kHz, +0.5 dB/-3 dB
  • Signal-to-noise ratio (SNR): >90 dB
  • Total harmonic distortion + noise (THD+N): <-85 dB (0.006%)
  • Channel separation: > 85 dB

Optical digital input

The digital audio input has the following electrical characteristics (nominal specifications), based on input of a 1 kHz sine wave at 0 dBFS input level, 24-bit sample depth, and 44.1 kHz sample rate (unless otherwise specified below):

  • FSI – input sample rates: 44.1 kHz, 48 kHz, or 96 kHz
  • Bits per sample: 16, 20, or 24
  • Signal-to-noise ratio (SNR): >130 dB
  • Total harmonic distortion + noise (THD+N): <-130 dB (0.0003%)

Sound output/digital audio output port

Line/Headphone output

The headphone output is automatically selected for audio output if no external S/PDIF optical digital output device is detected. The headphone output supports a stereo data stream at bit depths of 16, 20, or 24 bits per sample and at sample rates of 44.1 kHz, 48 kHz, or 96 kHz. The headphone output volume can be adjusted from 0.0 dB to -64 dB.

During playback of a 1 kHz sine wave at -3 dBFS voltage level, 24-bit sample depth, 44.1 kHz output sample rate, 100 k load (unless otherwise specified) the audio output has the following nominal specifications:

  • Jack type: 3.5 mm (1/8-inch) stereo combo
  • Maximum output voltage: 1.6 VRMS (+6.3 dBu)
  • Output impedance: <24 ohms
  • Frequency response: 20 Hz to 20 kHz, +0.5 dB/-3 dB
  • Signal-to-noise ratio (SNR): >90 dB
  • Total harmonic distortion + noise (THD+N): <-80 dB (0.007%)
  • Channel separation: >85 dB

S/PDIF optical digital output

The S/PDIF (Sony/Philips Digital Interface Format) optical digital output is automatically selected when an S/PDIF optical digital output device is detected on the external combination audio port. The S/PDIF optical digital output supports pulse-code modulation (PCM) and Arc Consistency Algorithm #3 (AC-3) audio formats with the following stereo data stream characteristics:

  • PCM: 16, 20, or 24 bits per sample at sample rates of 44.1 kHz, 48 kHz, or 96 kHz
  • AC-3: 16 bits per sample at sample rates of 44.1 kHz, 48 kHz, 88.2 kHz, 96 kHz, 176.4 kHz, or 192 kHz

The S/PDIF optical output channel status conforms to International Electrotechnical Commission (IEC) 60958-3 consumer mode digital audio.

During playback of a 1 kHz sine wave (S/PDIF output format at 0 dBFS output level, 44.1 kHz sample rate, 24-bit sample depth, unless otherwise specified) the digital audio output has the following nominal specifications:

  • Jack type: 3.5 mm (1/8-inch) stereo combo
  • Digital audio signal-to-noise ratio (SNR): >130 dB
  • Digital audio total harmonic distortion + noise (THD+N): <-130 dB (0.00003%)
Important: Information about products not manufactured by Apple is provided for information purposes only and does not constitute Apple’s recommendation or endorsement. Please contact the vendor for additional information.
Last Modified: Aug 22, 2011
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