KR20160031199A - Enhanced communication link using synchronization signal as link command - Google Patents

Abstract

The present invention relates to a communications system which performs communications through an in-transition control channel of a multimedia communications link by using synchronization signals which can also function as logical link commands. Synchronization indicators are exchanged between two communications devices so that the synchronization indicators can maintain synchronization of a logical link. At least two different types of synchronization signals, as the synchronization indicators, can be transmitted between two devices. A first synchronization signal is basically used to maintain the synchronization of the logical link. A second synchronization signal, instead of the first synchronization signal, is used to maintain the synchronization of the logical link. The second synchronization signal can be used to imply a virtual link command for displaying that the device successfully receives data through a virtual link or is ready to receive the data.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an improved communication link using a synchronization signal as a link command,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to data communication, and more particularly to maintaining channel synchronization in a multimedia communication link.

Devices that communicate over a control channel of a multimedia communication link (e.g., a Mobile High Definition Link (MHL)) have traditionally used a speculative transmission protocol. In this speculative transmission protocol, small fixed-length packets are exchanged. A device may speculatively transmit packets assuming that other devices have sufficient space in the buffer for data. For this reason, a data packet may need to be transmitted a plurality of times, and data transmission may be delayed as the data packet may be transmitted when another device does not have sufficient performance to receive or process the data packet . As a result, the latency of such communications can be large, which can slow data transmission between the devices.

Embodiments of the present invention are directed to an apparatus for communicating audiovisual data with other devices. The apparatus includes a receiving module and a transmitting module. The receiving module receives a request from another device to send a payload to the device over a full-duplex data link. The transmission module transmits the data to the second device. The data includes a set of synchronization indicators for maintaining synchronization of the full-duplex data link with other devices over the full-duplex data link. The transport module may also be configured to send a payload to the first device over a full duplex data link when the first device is determined that it is ready to receive the payload from the second device, And transmits the predetermined first signal to the other device.

In one embodiment, the forwarding module may be configured to forward the full duplex data link among a series of synchronization indicators to indicate the maintenance of synchronization of the full-duplex data link, without indicating that the first device is ready to receive the payload from another device. And transmits a predetermined second signal as one.

In one embodiment, the transport module is configured to transmit a payload of a first device over a full-duplex data link when it is determined that the device has received a payload from another device, And transmits the predetermined first signal to another device as one of the synchronization indicators.

In one embodiment, a set of synchronization indicators is transmitted periodically in a Time-Division Multiplexing (TDM) time slot.

Embodiments may also include sending a request to transmit a payload to another device over a full-duplex data link and sending a payload to a full-duplex data link when a predetermined first signal in a series of synchronization indicators is received at a receiving module of the device, To another device via a transmission module. The predetermined first signal indicates that the second device is ready to receive the payload. The data received by the receiving module includes a set of synchronization indicators for maintaining synchronization of the full-duplex data link with other devices over the full-duplex data link.

The teachings of the embodiments disclosed herein may be readily understood by considering the following detailed description in conjunction with the accompanying drawings.
1 is a high-level block diagram of a system for data communication in accordance with one embodiment.
2 is a diagram illustrating synchronization characters that are transmitted in time division multiplexed (TDM) time slots assigned to establish or maintain a logical link in the multimedia system of FIG. 1 according to one embodiment.
3 is a diagram illustrating a synchronization training sequence for establishing or maintaining a logical link in the multimedia system of FIG. 1 according to one embodiment.

The drawings and the following description are merely illustrative of various embodiments. It should be noted from the following discussion that alternative embodiments of the structures and methods described herein will be readily appreciated as feasible alternative embodiments that can be used without departing from the principles discussed herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to some of the embodiments, examples of which are illustrated in the accompanying drawings. It is noted that similar or identical reference numbers may be used practically anywhere in the figures and that they may represent the same or similar functionality.

Embodiments relate to communication over a full duplex control channel of a multimedia communication link by using synchronization indicators that can also function as logical link commands. The synchronization indicators are exchanged between the two communication devices to maintain synchronization of the logical link. At least two different types of synchronization signals may be transmitted as synchronization indicators between the two devices. The first synchronization signal is used basically to indicate that synchronization of the logical link is being maintained. The second synchronization signal is used in place of the first synchronization signal to indicate that synchronization of the logical link is being maintained. The second synchronization signal also functions as a logical link command to indicate that the device is ready to receive data over the full-duplex channel or that it has successfully received data.

Synchronization as described herein refers to the operational state of a logical link as defined by a particular protocol as being suitable for data transmission between two devices. Synchronization may be determined by exchanging and verifying synchronization indicators between two devices.

1 is a high-level block diagram of a multimedia system 100 for multimedia data communication in accordance with one embodiment. The multimedia system 100 includes a source device 110 that communicates with a sink device 120 via a multimedia communication link 130. The source device 110 is a source of audiovisual data streams. Examples of source devices 110 are mobile phones, digital video disk (DVD) players, Blu-ray players, cable boxes, Internet Protocol Television (IPTV) boxes, laptops, (IC). The sink device 120 may receive audiovisual data streams and may include functionality for displaying received audiovisual data streams. Examples of sink device 120 include liquid crystal crystal display (LCD) televisions, LCD monitors, or ICs in such devices.

The multimedia communication link 130 includes an audiovisual channel 132 and a physical control channel 134. The source device 110 is connected to the audiovisual channel 132 as well as to the control channel 134 via the interface 140. Sink device 115 is connected to audio channel 132 and control channel 134 video channel 152 and control channel 156 via interface 142. The interfaces 140 and 142 are physical elements, such as connectors, pins, drive circuits, or receive circuits, through which communication may occur.

The source device 110 transmits the audiovisual data streams to the sink device 120 via the audiovisual channel 132. The audiovisual channel 132 is a one-way and conveys video data streams from the source device 110 to the sink device 120. The audiovisual channel 132 may be implemented using a differential pair of wires. Alternatively, there may be a plurality of audiovisual channels 132 for transmitting one or more video data streams. The audiovisual data stream may be displayed at the sink device 120 or passed to another device for display.

The source device 110 and the sink device 120 also exchange control data via the control channel 134. The control channel 134 is bi-directional and full-duplex so that the source device 110 and the sink device 115 can simultaneously transmit control data. The control data transmitted over the control channel 134 may specifically include display data channel (DDC) commands, enhanced display identification data (EDID) data, and content protection codes. The control channel 134 may be implemented using a differential pair of wires or a single pair of wires. The control channel 134 may also transfer clocks from the source device 110 to the sink device 120.

In one embodiment, the multimedia communication link 130 is a mobile high definition link (MHL) and the control channel 134 is an enhanced control bus (eCBUS) for the MHL. However, embodiments of the present invention are not limited to MHL, and the multimedia communication link 130 may include embodiments that are high definition multimedia interface (HDMI) links or other types of multimedia communication links. The control channel 134 may additionally provide a high-speed bi-directional path for data transfer between the source device 110 and the sink device 120. [

To efficiently transmit data, a plurality of logical links may be multiplexed on one physical channel and transmitted from the source device 110. For this purpose, the control channel 134 may support a plurality of communication protocols in which each communication protocol is supported by one logical link. Each communication protocol may specify a different set of rules for the communication of different types of control data. For example, protocols for a high-throughput MHL sideband channel (eMSC) and a first generation MHL link control bus (CBUS1) may be supported.

The control channel 134 may allocate its bandwidth using time division multiplexing (TDM). Each logical link is assigned to one or more time slot locations within the TDM frame for transmission over the control channel 134 via the interface 140. The TDM frames are received and decoded to extract control data that is passed on to the appropriate protocol. A plurality of independent logical links may be assigned to the fixed portion of the control channel 134 bit times, thereby ensuring the fixed bandwidth and latency of each logical link. The bandwidth and latency over the control channel 134 is determined by the assignment of TDM slots and by the mode of the TDM slot.

The control channel 134 is a full duplex scheme so that data can be transmitted simultaneously in both directions (from the source device 110 to the sink device 120 and from the sink device 120 to the source device 110). Some protocols support bidirectional data flows. During the TDM time slots assigned to the protocols supporting bi-directional data flows, the source device 110 and the sink device 120 can simultaneously transmit and receive data over the control channel 134. In the illustrated example, the source device 110 includes a transmission module 112 and a receiving module 114, and the sink device 120 includes a transmitting module 122 and a receiving module 124. The source device 110 and the sink device 120 can transmit and receive data simultaneously with each other. For example, data transmitted by the sending module 112 of the source device 110 is received by the receiving module 124 of the sink device 120, and transmitted by the sending module 122 of the sink device 120 The transmitted data is received by the receiving module 114 of the source device 110.

Some protocols support block transactions. Block transactions support a more efficient means of data transfer using request and acknowledgment mechanisms at the beginning of a transaction. After the logical link is established, the block transaction starts from the requestor (e.g., source device 110) that sends the request command. The requestor (e.g., source device 110) may also send a count value indicating the size of the payload. The requestor's transmission module (e.g., the transmission module 112) determines that the requestor's receiving module (e.g., the receiving module 114) has received the request from the responder (e.g., sink device 120) It is possible to wait until it is received. When the transmission module time out from waiting, the transmission module returns to the idle state.

After receiving a logical link command indicating that the responder (e.g., sink device 120) has acknowledged the requester's command, the sending module (e.g., sending module 112) Logical link command to a receiving module (e.g., receiving module 124). The responder's receiving module (e.g., receiving module 124) is notified that the payload data follows directly after the logical link command. The requestor's transport module (e.g., transport module 112) continues to populate its channel with payload bytes to the size indicated by the responder's receive module (e.g., receive module 124). The requestor's transmission module (e.g., transmission module 112) may send a Cyclic Redundancy Check (CID) message to the responding receiver module (e.g., the receiving module 124) in the next TDM time slots after the last byte of the payload Check: CRC) value. In one embodiment, a 16-bit CRC is sent to indicate data bytes of a logical link packet, a 2-bit CRC is sent to indicate a logical link packet comprising a 1-byte header, a 3-bit CTC Is sent to indicate a logical link packet containing a 2-byte header.

The transmission module (e.g., the transmission module 112 or 122) may be configured such that the transmission module times out or the receiving module (e.g., the receiving module 114 or 124) acknowledge), negative-acknowledgment, or error). When the sending module times out, the requester may _retry at least a plurality of times (N _RETRY ) after the minimum interval (T _RETRY ). When the transmitting module receives a virtual link command, such as an acknowledgment, the virtual link transaction completes. When the transmitting module receives a virtual link command such as a negative acknowledgment or an error, the transmitting module may _retry the entire virtual link transaction from the start at least a plurality of times (N _RETRY ) after the minimum interval (T _RETRY ).

The source device 110 and the sink device 120 may each include a buffer. The sending module 112 and the receiving module 114 of the source device 110 are functionally similar to their corresponding portions in the sink device 120 (i.e., the sending module 122 and the receiving module 124). The transmission module 122 and the reception module 124 are thus also applied to the transmission module 122 and the reception module 124. Thus, the operations of the transmission module 112 and the reception module 114 described herein are also applied to the transmission module 122 and the reception module 124, Is omitted herein for brevity.

2 is a diagram illustrating synchronization characters that are transmitted in time division multiplexed (TDM) time slots assigned to establish or maintain a logical link in the multimedia system of FIG. 1 according to one embodiment. The bandwidth of the control channel 134 is divided into repeating time slots using TDM. In some embodiments, a mechanism for transferring arbitrary data between two devices (e.g., source device 110 and sink device 120) may be implemented over a logical link ≪ / RTI > In one embodiment, the data payload may be of any size (e.g., from 1 byte to 256 bytes) less than a predetermined number of bytes. The first byte of the data payload may be transmitted first, the second data of the data payload may be followed, the last byte of the payload may be transmitted last, and so on.

The source device 110 and the sink device 120 may use a set of synchronization indicators to maintain synchronization of the logical link between the source device 110 and the sink device 120. [ For example, the transmission module 112 transmits a default signal or a non-basic signal as synchronization indicators. Each of the synchronization indicators may be inserted by the transmission module 112 or the transmission module 122. [ The receiving module 124 or receiving module 114 receives the synchronization indicators and takes actions to re-establish the logical link if the synchronization indicators are not received as expected. A set of synchronization indicators may reside within a logical link data stream, within a logical link command, a logical link packet, or within a logical link transaction, or elsewhere. The logical link command includes one or two bytes sent by the requestor as part of a larger exchange or returned by the responder. The requestor is the device requesting to send the payload, and the responder is the device that responds to the request. The logical link packet includes an instruction having data bytes requested by the instruction sent from the requestor ' s transmission module. A logical link transaction includes packets transmitted and received between a transmitting module and a receiving module during an interval starting from an idle state and ending from an idle state. A logical link transaction is the exchange of closely-defined data between devices.

The control channel 134 may be logically partitioned into iterative time slots using TDM. The time slots for communications over the control channel 134 may be logically partitioned into source time slots and sink time slots. The source time slots represent TDM time slots for transmission of data from the source device 110 to the sink device 120 over the control channel 134 and sink time slots are allocated to the sink device 120 via the control channel 134. [ Lt; RTI ID = 0.0 > 110 < / RTI > The control channel 134 is a full-duplex channel and therefore data can be transmitted simultaneously in both directions using source time slots and sink time slots. In the example illustrated in FIG. 2, time slots 200 may be source time slots or sink time slots. As illustrated, time slots 200 are also organized into TDM frames, each of which includes N time slots (e.g., time slot 0 through time slot N-1). A TDM frame represents a cycle for transmission of data to N logical links.

Within the TDM frame 202, each time slot may be allocated for a logical link. For example, as illustrated, time slots 210, 211, 212, 213, and 214 in each corresponding TDM frame may be used to transmit data of a communication protocol as described above with reference to FIG. . Other time slots within the TDM frame may be allocated for different communication protocols (e. G., ECBUS, Remote Button Protocol commands, tunnel CBUS of the MHL protocol).

The synchronization indicators are periodically transmitted to check for loss of synchronization in one or more communication protocols used to transmit data over the control channel 134 or to maintain synchronization of the logical link. In the example illustrated in FIG. 2, synchronization indicators for the logical link are sent in time slots 210 and 214. The synchronization indicators may be periodically transmitted on a TDM time slot. In some embodiments, the self-synchronization indication are transmitted on the TDM time slot of the subsequent bytes of the plurality (N _{SYNC _ INDICATOR).} For example, in the example illustrated in Figure 2, the first synchronization indicator is transmitted in time slot 210, the second synchronization indicator is at time slot 214 that appear after the bytes of the plurality (N _{SYNC _ INDICATOR)} . In some embodiments, the plurality of bytes between two consecutive synchronization indicators may be at least a predetermined number of bytes (e.g., 24 bytes). A transmission module (e.g., a transmission module 112, a transmission module 122) of the device may transmit a primary signal or a non-primary signal in the TDM slots 210 and 214.

Since the time slot for the logical link may be at any point in the protocol transaction, synchronization indicators may be present at any point in the logical link transaction. For example, the synchronization indicators may be between bytes of a two-byte logical link instruction or in a sequence of bytes in a logical link packet. In some embodiments, the synchronization indicator may be anywhere in the entire logical link transaction. The receiving module of the device may periodically check for the presence of synchronization indicators in scheduled TDM time slots to transmit synchronization indicators. The transmission module may periodically transmit the basic signal as synchronization indicators in the TDM time slots.

Instead of transmitting the base signal as synchronization indicators, the transmission module may transmit the non-base signal different from the base signal as synchronization indicators. Since a TDM time slot for transmitting synchronization indicators may be at any point during the course of a logical link transaction, when the transmitting module of the device is busy transmitting data packets, Lt; / RTI > In one embodiment, a non-basic signal is transmitted when a scheduled TDM slot for synchronization indicators is in the middle of a data packet. The TDM time slot may exist before the end of the data packet. When transmitting such a non-basic signal as a synchronization indicator, the non-basic signal may be used to indicate a logical link command, such as acknowledgment or acknowledgment. A logical link command called acknowledgment is used to acknowledge the request to transmit the payload. That is, the transfer request is granted. A logical link command called acknowledgment is used to acknowledge receipt of the payload. That is, the data is received without error. In other words, rather than sending an express logical link command, a non-basic signal is sent to indicate the logical link command and as a synchronization indicator.

For example, a requestor may request to send a payload to another device. The requestor's transport module does not transmit the payload until it receives a logical link command (e.g., acknowledgment) from the other corresponding device. After determining that the responder is ready to receive the payload, the responder's sending module may send a non-default synchronization signal to acknowledge the supplicant's request to send the payload as well as to confirm the synchronization of the logical link have. The non-primary synchronization signal is transmitted during transmission of the data packet. After the requestor's receiving module receives the non-default synchronization signal, the requestor's sending module may continue to send a payload that conforms to the protocol of the logical link. After the responder successfully receives the payload sent from the supplicant, the responder's transmission module may send a non-default synchronization signal to the requester receiver to indicate acknowledgment of receipt of the payload as well as maintaining link synchronization. The non-default synchronization signals are used only when the link command is ready to be transmitted in the middle of the link transaction and the time slot for the synchronization indicator is before the end of the link transaction.

In some embodiments, a timeout may occur when a logical link command (e.g. acknowledgment, negative acknowledgment, acknowledgment, start of data byte series, or error) is not received within a time frame. A logical link command of negative-acknowledgment is used to indicate that the device can not receive the payload. That is, data can not be received because the buffer is full. The logical link instruction, the start of the data byte series, is used to indicate the beginning of the data byte series. Receiving modules able to time out a predetermined time period (T _{RESP TMOUT _ _ MAX)} after the standby, and the following, the transmission module may time out a predetermined time period (T _{RESP TMOUT _ _ MIN)} and then over the air. Non-basic synchronization signals received in the idle state are ignored. A non-basic signal received when a logical link command is not scheduled is treated as an invalid command. Upon receiving an invalid logical link command within the data transfer portion of a logical link transaction, the device may force an error. For example, the transmitting module of the device may transmit a reverse CRC at the end of the data stream. When an invalid logical link command is received at any other time during a logical link transaction, the device may abandon the logical link transaction, which may cause a timeout at the receiving module and the transmitting module of the device.

A missing synchronization indicator may indicate a possible loss of synchronization. After the number of consecutive synchronization indicator mismatches reaches a threshold, the logical link may be considered to have lost synchronization. In some embodiments, the threshold is 4 bytes. The logical link that lost synchronization may return to the synchronization training sequence. The synchronization training sequence is typically performed short after the control channel 134 is connected to start the logical link. However, the synchronization training sequence may also be performed when the link is determined to have lost synchronization.

3 is a diagram illustrating a synchronous training sequence for establishing or maintaining a logical link in the multimedia system 100 of FIG. 1 in accordance with one embodiment. The transmission module of the device may perform synchronization training at the start of a logical link or in the case of a loss of synchronization error condition. The logical link may lose its synchronization when the number of consecutive synchronization indicator mismatches reaches a threshold. The device may perform synchronization training at any point in time. Sequence of synchronization characters will be sent until two of the following conditions will be met: 1) The transmission module is made at least transmitting the synchronization characters of a plurality (N _{_ INIT _ SYNC),} and 2) a receiving module of the transfer of the other device would have received a synchronization character of at least the plurality (N _{_ _ INIT sYNC)} from the transmission module. The transfer module of the device continues to transfer the synchronization characters to the next scheduled time slot for the synchronization indicator.

For example, as illustrated, time slots 300 may be transmitted to a transmission module (e.g., a source device 110) of a first device (e.g., source device 110) (E.g., the transmission module 112), and the time slots 330 are allocated to the transmission module of the second device (e.g., sink device 120) For example, the transmission module 122). The data transmitted over time slots 330 is received by the receiving module of the first device (e.g., source device 110).

The synchronization training process starts when the transmission module of the first device starts transmission of synchronization characters. Transmission module 112 which transfers the synchronization characters 320 of the plurality (N _{_ INIT _ SYNC),} the receiving module 124 to receive at least a synchronization character to 350 of the plurality (N _{_ INIT _ SYNC)} And continues to transmit synchronization characters 322 until the next scheduled time slot 313 occurs to transmit the synchronization indicator. At the same time, the transmission module 122 is synchronization characters of a plurality (N _{_ INIT _ SYNC)} synchronization and send the characters to 350, a receiving module 124, at least a plurality (N _{_ INIT _ SYNC)} of 320 And continues to transmit synchronization characters 352 up to the next scheduled time slot 344 to transmit the synchronization indicator.

Synchronization characters are to be sent periodically, the synchronization indicator are transmitted on the TDM time slot, after the byte to the plurality (N _{SYNC INDICATOR _)} with respect to the logical link transmission. In the illustrated example, after both receive modules 114 and 124 receive at least the minimum number of synchronization characters, transmission module 112 transmits a first synchronization indicator in TDM timeslot 313, and TDM Transmits a second synchronization indicator in a TDM timeslot 317, which is the next TDM time slot after a plurality of bytes starting from time slot 313. Transmission module 122 transmits a first synchronization indicator in TDM timeslot 344 and transmits a second synchronization indicator in TDM time slot 348, which is the next TDM time slot after a plurality of bytes starting from TDM time slot 344. [ Send the indicator.

Upon reading this disclosure, one of ordinary skill in the art will understand additional alternative designs for multimedia systems for data communication over the full duplex control channel of a multimedia communication link. Thus, while specific embodiments and applications of the present invention have been illustrated and described, it is to be understood that the embodiments are not limited to the precise configuration and components described herein, and that various modifications, changes, and variations And details of the method and apparatus of the present invention disclosed herein without departing from the spirit and scope of the present invention as defined in the appended claims.

Claims (20)

A first device for communicating audiovisual data,
A receiving module configured to receive a request to transmit a payload from the second device to the first device over a full-duplex data link; And
As a transmission module:
Transmitting data to the second device, the data comprising a set of synchronization indicators for maintaining synchronization of the full-duplex data link with the second device over the full-duplex data link; and
In response to determining that the first device is ready to receive the payload from the second device, causing the second device to transmit the payload to the first device over the full-duplex data link And transmit the predetermined first signal as one of the series of synchronization indicators to the second device.
The method according to claim 1,
Wherein the transmission module does not indicate that the first device is ready to receive the payload from the second device, And to transmit a predetermined second signal as one.
The method according to claim 1,
Wherein the transmission module is responsive to a determination that the first device has received the payload from the second device and to receive the payload by the first device over the full duplex data link to the second device And to transmit the determined first signal as one of the series of synchronization indicators to the second device for acknowledging the first signal.
The method according to claim 1,
Wherein the set of synchronization indicators is periodically transmitted in a Time-Division Multiplexing (TDM) time slot.
The method of claim 4,
Wherein the set of synchronization indicators are transmitted at least every predetermined number of bytes.
The method of claim 4,
Wherein the transmitting module is configured to transmit the predetermined first signal in response to determining that the TDM slot is in the middle of a data packet.
The method according to claim 1,
Wherein a size of the payload is configured to be less than a predetermined number of bytes.
The method according to claim 1,
Wherein the transmission module is further configured to transmit at least a predetermined number of synchronization characters to perform synchronization training,
Wherein the receiving module is further configured to receive at least the predetermined number of synchronization characters transmitted from the second device.
The method according to claim 1,
And wherein the transmitting module is configured to time out in response to a wait for more than a threshold time.
A first device (requester) for audiovisual data communication,
A receiving module configured to receive data from a second device, the data comprising a series of synchronization indicators for maintaining synchronization of the full-duplex data link with the second device over a full-duplex data link; And
As a transmission module:
Send a request to transmit the payload to the second device over the full-duplex data link, and
And to transmit the payload to the second device over the full-duplex data link in response to receiving at the receiving module a predetermined first signal in the set of synchronization indicators, The transmission module indicating that the second device is ready to receive the payload.
The method of claim 10,
Wherein the receiving module is configured to verify the set of synchronization indicators including the predetermined first signal and a predetermined second signal.
The method of claim 10,
Wherein the receiving module is configured to determine that the full-duplex data link lost synchronization in response to a determination that the number of consecutive mismatches of the series of synchronization indicators received at the receiving module exceeds a threshold, .
The method of claim 10,
Wherein the receiving module is further configured to detect another predetermined first signal in the set of synchronization indicators as an acknowledgment of receipt of the payload transmitted by the second device over the full duplex data link, .
The method of claim 10,
Wherein the set of synchronization indicators is received periodically in a Time-Division Multiplexing (TDM) slot.
The method of claim 10,
And ignore the synchronization indicator received outside the TDM slot.
15. The method of claim 14,
Wherein the set of synchronization indicators are received at least every predetermined number of bytes.
The method of claim 10,
Wherein a size of the payload is configured to be less than a predetermined number of bytes.
The method of claim 10,
Wherein the transmission module is further configured to transmit at least a predetermined number of synchronization characters to perform synchronization training of the full-duplex data link,
Wherein the receiving module is further configured to receive at least the predetermined number of synchronization characters transmitted from the second device.
The method of claim 10,
Wherein the receiving module is configured to time out in response to a wait below a threshold time.
A method for communicating audiovisual data,
In a first device, transmitting first synchronization signals to maintain synchronization of the full-duplex data link with a second device over a full-duplex data link;
Receiving, at the first device, a request to transmit a payload from the second device to the first device over the full-duplex data link;
Determining whether the first device is ready to receive the payload from the second device in response to receiving the request; And
In response to a determination that the first device is ready to receive the payload, to cause the second device to transmit the payload to the first device and to transmit data over the full- And transmitting a second synchronization signal different from the first synchronization signal to the second device to indicate that the second synchronization signal has been received.

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