9 Electrical Man Machine Interface (EMMI)

3GPP44.014Individual equipment type requirements and interworkingRelease 17Special GSM/EDGE conformance testing functionsTS

9.1 Use of the EMMI

Conformity tests of mobile stations are made using the system simulator specified in Annex 4.

Test signals are sent on the Um interface, and actions of the MS are registered. The Electrical Man Machine Interface (EMMI) is a half duplex communication link between the SS and the MS by which it is possible to automatically register the status, indications and performance of the MS.

It is also possible to simulate actions normally made by the user on the keyboard of the MS.

9.2 Formal aspects

i) The EMMI is optional for the ME.

ii) The EMMI is mandatory for the SS.

iii) If the EMMI is to be used in conformance testing of an MS, it shall be possible to connect the SS to a connector on the MS, or to an adapter connected to the same MS. If an adapter is to be used, it shall be provided by the manufacturer.

iv) If the MS fulfils the requirements performed with the use of an EMMI, the MS is regarded as having passed that test.

v) If the MS is rejected in a test performed with EMMI, the test shall be repeated on the same mobile with the device carrying the EMMI to the MS removed. The MS shall be regarded as fulfilling the requirements, if it then passes the test.

vi) When using the EMMI, the MS does not necessarily conform to the RF requirements. Therefore, tests concerning Rx and Tx parameters on MS with integral antenna and cabinet radiation tests for all types of MS will never be performed with the use of the EMMI.

9.3 Layered structure of the interface

The definition of the EMMI is divided into three different layers. On layer 1 the use of a 25-pole socket with standard electrical characteristics for serial communication is defined. On layer 2, an extremely simple frame oriented protocol is defined. On layer 3, messages for control and verification of functions and indications are defined. Each layer is defined independently of surrounding layers, and is therefore easy to replace.

The EMMI protocol structure takes into account that the SS only sends and receives layer 3 frames when the corresponding step within a test case is to be performed.

9.4 Terminology

EMMI Electrical Man Machine Interface

MI Message Identifier

ME Mobile Equipment

MS Mobile Station

SS System Simulator

Frame Used on layer 2 to transfer messages to and from layer 3

Message Information on layer 3

9.5 Description of the EMMI

9.5.1 EMMI, Layer 1

9.5.1.1 Mechanical and electrical characteristics

If implemented, the EMMI interface shall use the same connector as the Digital Audio Interface (DAI), described in sub-clause 10.3.

The pin assignments for the EMMI shall be as follows:

Pin

Function

Source

2

Transmitted data

SS

3

Received data

MS

7

EMMI signal ground

The electrical characteristics of the interface shall be as given in sub-clause 10.3.2.

9.5.1.2 Transmission and reception characteristics

The EMMI uses asynchronous serial data transmission with 1 start bit (S), 8 data bits (D1 to D8), no parity and 1 stop bit (E).

Table 3: Use of start and stop bits

S

D1

D2

D3

D4

D5

D6

D7

D8

E

The conditions on start and stop characters are defined in REC CCITT V.1.

The transmission rates are: 600, 1200, 2400, 4800, 9600 bits per second. The ME shall support at least one of these speeds.

The SS will adapt its rate (manually or by MMI) to this ME rate.

9.5.2 EMMI, layer 2

9.5.2.1 General structure

On layer 2, frames are used to carry data from higher layers. Frames consist of one or several octets. One frame with variable length is used to carry data from higher layers, and four other frames with the length of one character is used to control the flow of frames.

9.5.2.2 Control frames

Special frames have been assigned to control the flow of frames on layer 2. They are only one octet long.

Table 4: Characters for flow control

Abbr.

Meaning

Dec.value

Bit pattern

ACK

Acknowledge

06

0000 0110

NAK

Not Acknowledge

21

0001 0101

XON

Resume sending data

17

0001 0001

XOF

Stop sending data

19

0001 0011

9.5.2.3 Frame structure

Two octets, called characters, indicate start and stop of I-frames.

Table 5: Start and stop characters

Abbr.

Meaning

Dec.value

Bit pattern

STX

Start of data

02

0000 0010

ETX

End of data

03

0000 0011

Information from higher layers are transferred in I-frames with the following structure.

Table 6: Information structure in I-frames

Field name

No of octet

Value

Start at octet no

Note

Start

1

Character STX

1

–

Length

1

Length of data

2

a1)

Data

0-255

Content of data

3

a2)

Check

1

Error detection

Length+2

a3)

End

1

Character ETX

Length+3

NOTE a1) Length: The total number of data octets in the data field of the frame is calculated. The value shall be in the range of (0..255 decimal). The corresponding binary value is put into the length field.

NOTE a2) Data: Data to and from higher layers are in the form of octets (groups of 8 digital bits).

NOTE a3) Check: Longitudinal checksum is created by exclusive OR on all characters starting with the Start field and ending with the last octet before the Check field. The value, one octet, is mapped into the Check field.

9.5.2.4 Flow of I-frames on layer 2

9.5.2.4.1 Transmission of frames

A multiple frame starts with the first octet being the character STX and stops with the last octet with content ETX. The time between the start bits of two consecutive octets shall not be longer than T22.

Octet n

octet n + 1

< T22 >

The time between two frames is measured from the start bit of the last octet of the nth frame to the start bit of the first octet of the n+1st frame. The time between two consecutive frames shall not be less than T23.

STX

Frame n

ETX

STX

frame n+1

ETX

< T23 >
9.5.2.4.2 Reception of frames

Start of a frame is defined as (more than T22*2 since previous reception of octet) AND (reception of STX).

End of a frame is defined as (reception of ETX in octet number (length+2)) OR (more than T22*2 since last reception of octet).

9.5.2.4.3 Use of ACK and NAK on receiving side

ACK is used by the MS to acknowledge a frame on receiving side if all the following conditions are fulfilled. Otherwise NAK is used.

1) The content of Start field is STX.

2) The content of Check field corresponds to the exclusive OR sum of previous octets in the frame.

3) The content of the last octet is ETX.

NAK is used by the SS to request retransmission of a frame. Otherwise ACK is used.

NOTE: NAK shall not be used for layer 3 errors, if the layer 2 frame is correct. If the meaning of a layer 3 message is undefined or not performable, then the problem is solved with layer 3 messages.

9.5.2.4.4 Use of XON and XOF

XON and XOF are used for flow control of layer 2.

XOF is sent if the unit (MS or SS) due to internal processing is not capable of receiving a following frame when a frame is being received.

XON is sent if XOF has been sent previously, but the reason for that XOF-transmission no longer exists.

9.5.2.4.5 Parameters on layer 2

Table 7: Timer values on layer 2

Bit rate

Value of T22

Value of T23

600

25.0 ms

58.3 ms

1200

12.5 ms

29.2 ms

2400

6.3 ms

14.6 ms

4800

3.1 ms

7.3 ms

9600

1.6 ms

3.6 ms

9.5.3 EMMI, layer 3

9.5.3.1 Message structure

Messages are used on layer 3. They are defined by Message Identifiers (MI) in the range of (0..255). The message identifier is always the first, and often the only, octet of the message.

Table 8: Use of message identifiers

MI

Use

0-49

Not used.

50-179

General messages. All undefined values reserved for further evolution of the EMMI.

180-209

ME-type dependent blocks, may be used by the SS as a sender or receiver, if so requested by the manufacturer. Undefined values available for the manufacturer.

210-239

ME-type dependent blocks, never to be used by the SS in conformance testing. Undefined values available for the manufacturer.

240-255

Reserved for L3 error handling. All undefined values reserved for further evolution of the EMMI.

NOTE 1: Layer 2 is transparent, but to avoid unnecessary interference from layer 3, MI with the same value as control frames on layer 2 are not used.

Most of the messages, especially in the direction SS – MS contain only one octet, the message indicator. Some of the messages, especially in the direction MS – SS are quite long.

NOTE 2: If the interface is limited only to the minimum required for automatic conformity testing with the electrical man machine interface, then the included L3 messages should be RQTI, KEYS, BEL1, BEL0, HOK1, HOK0, BCAP and RSTI.

Table 9: Block types

MI

Source

Value

Abbr.

Meaning

MS

SS

051

VOL1

Increase volume (***)

X

052

VOL0

Decrease volume (***)

X

053

RQTS

Request for table, status

X

054

RQTI

Request for table, indication

X

055

RQPL

Request for power level

X

056

RQBE

Request for bell status

X

057

RQSM

Request for short message

X

058

KEYS

Perform keystroke sequence

X

060

BEL1

Indication user alert on

X

061

BEL0

Indication user alert off

X

064

HOK1

Hook on

X

065

HOK0

Hook off

X

070

BCAP

Selection of bearer capability

X

080

STPO

Set power level

X

091

RSTS

Response table, status

X

092

RSTI

Response table, indication

X

093

RSPO

Response, power level

X

101

RXSM

Received short message

X

102

RXSN

No short message received

X

240

ER00

Internal malfunction detected

X

241

ER01

L3 message not recognized

X

X

242

ER02

L3 message not performable

X

255

RESE

Perform hardware and software reset

X

NOTE 3: Functioning of this should be verified, as the volume control in the ME might be of another type (non-incremental).

9.5.3.2 Definition of messages

Messages are defined in the order of the value of the message identifier.

051 VOL1 Increase volume

052 VOL0 Decrease volume

Increase/decrease volume in the loudspeaker by one step.

8

7

6

5

4

3

2

1

Octet

1

Message identifier

053 RQTS Request for table, status

054 RQTI Request for table, indication

055 RQPL Request for power level

On receiving a request message RQxy, the corresponding table RSxy shall be sent.

8

7

6

5

4

3

2

1

Octet

1

Message identifier

056 RQBE Request for bell status

On receiving a request message RQBE, the internal user alert status (BEL1 or BEL0) shall be sent. BEL1 and BEL0 will indicate whether the ringing or alert procedure has been activated or not. (See also the definition of BEL1 and BEL0).

8

7

6

5

4

3

2

1

Octet

1

Message identifier

057 RQSM Request for short message

In response to the RQSM request the MS shall send either the short message type using the message RXSM or, in case of no short message received, the message RXSN.

8

7

6

5

4

3

2

1

Octet

1

Message identifier

058 KEYS Perform keystroke sequence

Perform the MS function related to the received keystroke sequence.

8

7

6

5

4

3

2

1

Octet

1

Message identifier

2

First key

….

N

Key Number N-1

The possible keystroke sequences are based on the basic public man machine interface as defined in 3GPP TS 22.030. There exists a minimum set of key characters.

The codes associated with these characters are defined as follows:

Key

Code (decimal)

#

35

*

42

+

43

0

48

1

49

2

50

3

51

4

52

5

53

6

54

7

55

8

56

9

57

END (function)

18

SEND (function)

20

060 BEL1

Indication user alert on

061 BEL0

Indication user alert off

Indication user alert shall indicate, on request of the SS, the internal status of the alert or ringing procedure. For this purpose, the SS shall send the RQBE (request for bell status) message to the MS.

BEL1 shall indicate that the alert procedure is active.

BEL0 shall indicate that the alert procedure is not active.

8

7

6

5

4

3

2

1

Octet

1

Message identifier

064 HOK1 Hook on

065 HOK0 Hook off

Control of the hook. The hook on/off command shall action the normal procedure associated with physically lifting the handset and replacing it whatever that maybe.

8

7

6

5

4

3

2

1

Octet

1

Message identifier

070 BCAP Selection of bearer capability

The EMMI BCAP message shall change the default bearer capability on all future calls made via the EMMI "perform keystroke sequence" message. The new default bearer capability shall be in effect until the ME is switched off or until the ME receives another EMMI BCAP message.

8

7

6

5

4

3

2

1

Octet

1

Message identifier

2

Bearer capability
(see note)

NOTE: The field "bearer capability" in the BCAP message is mandatory and is coded bit for bit exactly as the "bearer capability" information element as described in 3GPP TS 44.018, beginning with octet 2 (length of the bearer capability contents). Because the "bearer capability" is mandatory, the first byte of the field shall be the length of the bearer capability content and not the bearer capability information element identifier.

080 STPO Set power level

Used to control the Tx power level of the ME.

8

7

6

5

4

3

2

1

Octet

1

Message identifier

2

Power level
(see note)

NOTE: The power level is defined as the 2nd octet of the power command information element in 3GPP TS 44.018.

091 RSTS Response table, status

Response table status is sent as an answer to the corresponding request.

8

7

6

5

4

3

2

1

Octet

1

Message identifier

F1

F2

2

Statis fiels
(see note)

F3

NOTE: F1

0 0 0 0 Spare

F2 (1=yes, 0=no)

Bit 4 L2 link on SACCH established

Bit 3 Speech connection on TCH establ

Bit 2 Listening to BCCH

Bit 1 SDCCH established

F3

Bit 8 Frequency hopping (yes/no)

Bit 7-1 ARFCN of BCCH of serving cell

092 RSTI Response table, indication

Response table indication send as an answer to the corresponding request.

8

7

6

5

4

3

2

1

Octet

1

Message identifier

F1

F2

2

Indication field
(see note)

NOTE: F1

0000000 Spare

F2 (yes=1, no=0)

Bit 1 Service indication On (yes/no)

093 RSPO Response, power level

Response power level is sent as an answer to the corresponding request.

8

7

6

5

4

3

2

1

Octet

1

Message identifier

F1

F2

2

Power Level
(see note)

NOTE: The power level is defined as the 2nd octet of the power command information element in 3GPP TS 44.018

101 RXSM Received short message

The message RXSM has to be sent by the MS in response to the RQSM request if a short message has been received.

8

7

6

5

4

3

2

1

Octet

1

Message identifier

2

SM field octet 1
(see note)

….

N

SM field octet N-1

NOTE: The SM field is defined as the content of the data field short message storage defined in 3GPP TS 51.011, excluding byte 1, as follows:

1 byte NULL value

12 bytes TP Originating Address

12 bytes TS Service Centre Address

1 byte TP Protocol Identifier

1 byte TP Data Coding Scheme

7 bytes TP Service Centre Time Stamp

1 byte TP User Data Length

up to 140 bytes TP User Data.

If the length of the address for TP and for TS service centre is less than 12 bytes, the remaining bytes are filled with null values.

102 RXSN No short message received

The message RXSN has to be sent by the MS in response to the RQSM request if no short message has been received.

8

7

6

5

4

3

2

1

Octet

1

Message identifier

240 ER00 Internal malfunction detected

Used to indicate to the SS that the MS has discovered an internal error. This error message is to be handled in the same manner as the layer 3 error messages (only to be sent to the SS in response to a Layer 3 message received at the MS).

8

7

6

5

4

3

2

1

Octet

1

Message identifier

2

Error indication

NOTE: The error indicator is defined by the manufacturer of the ME.

241 ER01 L3 message not recognized

Used by the receiver to indicate to the sender that the message was correctly received, but ignored due to the fact that it was not understandable (e.g. a KEYS message with one or many values which are not part of the standard set of keys for the MSE). The message to the MS implies a request for re-sending the latest message sent.

8

7

6

5

4

3

2

1

Octet

1

Message identifier

242 ER02 L3 message not performable

Used by the receiver to indicate to the sender that the message was understood, but not performable due to intentional lack of functionality in the MS (e.g. as answer to a CALL message containing a type of service which the MS is not able to use) or to a message requesting a change to a state already existent.

8

7

6

5

4

3

2

1

Octet

1

Message identifier

255 RESE Perform HW and SW reset

The MS shall perform a total reset. The MS shall behave as if it has been switched "off" and "on".

8

7

6

5

4

3

2

1

Octet

1

Message identifier