ANNEX B
(to Recommendation X.21)
Interface signalling sequence diagrams and time–out operations
Definition of symbol used to illustrate time–out operation
in the signalling sequence diagrams:

CCITT-25052

FIGURE B-1/X.21	CCITT-25064

FIGURE B-2/X.21	CCITT-25074

FIGURE B-3/X.21	CCITT-61411

ANNEX C
(to Recommendation X.21)
DTE time–limits and DCE time–outs
C.1	DTE time–limits
	Under certain circumstances this Recommendation requires the DCE to respond to a signal from the DTE within a stated maximum time. If any of these maximum times is exceeded, the DTE should initiate the action indicated in Table C–1/X.21. To maximize efficiency, the DTE should incorporate time–limits to send the appropriate signal under the defined circumstances summarized in Table C–1/X.21. The time–limits given in the first column are the maximum times allowed for the DCE to respond and are consequently the lower limits of the times a DTE must allow for proper network operation. A time–limit longer than the time shown may be optionally used in the DTE; for example, all DTE time–limits could have one single value equal to or greater than the longest time–limit shown in this table. However, the use of a longer time–limit will result in reduced efficiency of network utilization. The actual DCE response time should be as short as is consistent with the implementing technology and in normal operation should be well within the specified time–limit. The rare situation where a time–limit is exceeded should only occur when there is a failure in DCE operation.
	The time–limits and actions for loop testing are given in Table C–3/X.21.
C.2	DCE Time–outs
	Under certain circumstances this Recommendation requires the DTE to respond to a signal from the DCE within a stated maximum time. If any of these maximum times is exceeded, a time–out in the DCE will initiate the actions summarized in Table C–2/X.21. These constraints must be taken into account in the DTE design. The time–outs given in the first column of the table are the minimum time–out values used in the DCE for the appropriate DTE response and are consequently the maximum times available to the DTE for response to the indicated DCE action. The actual DTE response time should be as short as is consistent with the implementing technology and in normal operation should be within the specified time–out. The rare situation where a time–out is exceeded should only occur when there is a failure in the DTE operation.
	The time–outs and actions for loop testing are given in Table C–4/X.21.

TABLE C–1/X.21
DTE time–limits
Time–limit	Time–limit number	Started by	Normally
terminated by	Preferred action to be taken
when
time–limit exceeded	
3 s	 T1	Signalling of call request (state 2)	 Reception of proceed–to–select (state 3)	 DTE signals DTE ready (state 1)	
20 s	 T2	Signalling end–of–selection or DTE waiting (direct call) (state 5)	 Reception of call progress signals, DCE provided information, ready for data or DCE clear indication (states 7, 10A, 12 or 19)	 DTE signals DTE clear request (state 16)	
6 s	 T3A	Reception of call progress signals or DCE–provided information (states 7 or 10A). Restarted by additional call progress signals or DCE–provided information (states 7 or 10A) (see Note 2)	 Reception of ready for data or DCE clear indication (states 12 or 19)	 DTE signals DTE clear request (state 16)	
60 s	T3B
(see Note 1)	Reception of applicable call progress signals (state 7). Restarted by additional call progress signals or DCE provided information (states 7 or 10A)
(see Note 2)	 Reception of ready for data or DCE clear indication
(states 12 or 19)	 DTE signals DTE clear request (state 16)	
2 s	 T4A	Signalling of proceed with call information (state 9B). Restarted by reception of call information (state 10C)  (see Note 2)	 Reception of end of call information character or DCE clear indication (state 19) or DCE waiting (state 6C)	 DTE signals DTE clear request (state 16)	
6 s	 T4B	Signalling of call accepted (states 9 and 9C). Restarted by reception of DCE–provided information (state 10B) (see Note 2)	 Reception of ready for data or DCE clear indication (states 12 or 19)	 DTE signals DTE clear request (state 16)	

TABLE C–1/X.21 (cont.)
Time–limit	 Time–limit number	 Started by	 Normally terminated by	Preferred action to be taken
when
time–limit exceeded	
2 s	T5	Change of state to DTE clear request (state 16)	 Change of state to DCE read11y (state 21)	DTE regards the DCE as DCE not ready and signals 	
2 s	 T6	Change of state to DTE clear confirmation
(state 20)	 Reception of DCE ready
 (state 21)	DTE ready
(state 18)	
0,2 s	 T7	 Change of state to ready (state 1) when charge information (state 10B) has been requested	Reception of incoming call (state 8)	 DTE returns to normal operation and may note absence of charge information (state 10B)	
 Note 1 – T38 shall be used when receiving CPS 01 and may also be used when receiving other CPS in code group 0.
Note 2 – Restart means time–out set to ZERO and restarted.

TABLE C–2/X.21
DCE time–outs
Time–out	 Time–out number	 Started by	 Normally terminated by	 Action to be taken when time–out expires	
36 s	 T11	 DCE signalling of proceed–to–select 
(state 3)	DCE reception of end–of–selection signal or in the case of direct call, DTE waiting (state 5)	

DCE will signal DCE clear indication (state 19) or	
6 s	T12	DCE signalling of proceed–to–select
(state 3)	DCE reception of first selection character or in the case of direct call, DTE waiting (state 5)	 transmit appropriate call
progress signals (state 7)
followed by DCE clear 
indication (state 19)	
6 s	T13	DCE reception of nth selection character (state 4)	 DCE reception of (n + 1)th selection character or end–of–selection signal		
0,5 s	T14A	DCE signalling of incoming call (state 8)	 Signalling of proceed with call information (state 9B) or call 	 The DTE is noted as not answering. The DCE will signal 	
60 s	T14B (see Note 1)		accepted (state 9) or call collision (state 15)	ready (state 1)	
20 s	T14C (see Note 2)	DCE transmitting end of call information character. Restarted by state 25 DTE–provided information (see Note 3)	 Change of state to call accepted (state 9C)	 DCE will signal DCE clear indication (state 19) or transmit appropriate call progress signals followed by DCE clear indication (state 19)	
0,5 s	T15	 Change of state to DCE clear indication (state 19)	 Change of state to DTE clear confirmation (state 20)	 DCE will signal DCE ready and mark DTE uncontrolled not ready (state 24)	
100 ms	T16	 Change of state to DCE ready (state 21)	 Change of state to ready (state 1)	 DCE will mark DTE uncontrolled not ready (state 24)	
Note 1 – T14B will be provided when manual answering DTEs are allowed. It is not envisaged that manual answering DTEs will use the enhanced sub–addressing procedure (see § 4.1.6.2.2).
Note 2 – T14C applies only to enhanced sub–addressing.
Note 3 – Restart means time–out set to ZERO and restarted.

TABLE C–3/X.21
DTE time–limits for loop testing
Time–limit	 Time–limit number	 Started by	 Normally terminated by	 Preferred action to be taken when time–limit expires	
2 s	 T20A	 DTE sending the loop command (state L21)	 DCE signalling loop confirmation (state L22)	 DTE stops sending loop command and enters any state 	
6 s	 T20B	 DTE sending the loop command (state L31)	 DCE signalling loop confirmation (state L32)	or signals DTE clear request 
(state 16)	
2 s	 T21	 DTE sending loop 2 clear request (state L24A or L24B)	 DCE signalling loop 2 clear confirmation (state L25)	 DTE signals DTE clear request (state 16)	
TABLE C–4/X.21
DCE time–outs for loop testing
Time–out	 Time–out number	 Started by	 Normally terminated by	 Action to be taken when time–out expires	
Duration is a national option	 T22	 DCE signalling receive loop 2 command (state L26)	 DCE reception of loop released (state L28) or test data (state L23) or DTE clear confirmation (state 20)	 DCE at the tested side causes the connection to be cleared	
 Duration is a national option	 T23	 Test data (state L23) being received by the tested DCE	 Loop released (state L28) or DTE clear confirmation (state 20) being received by the tested DCE	 DCE at the tested side causes the connection to be cleared	

ANNEX D
(to Recommendation X.21)
Formats of selection, call progress, and
DCE–provided information signals
	The following description uses Backus Normal Form as the formalism for syntactic description. A vertical line “ | ” separates alternatives.
<*>	: : = IA 5 character 2/10
<+>	: : = IA 5 character 2/11
< , >	: : = IA 5 character 2/12
<–>	: : = IA 5 character 2/13
< . >	: : = IA 5 character 2/14
</>	: : = IA 5 character 2/15
<h>	: : = IA 5 characters 3/0–3/9
<:>	: : = IA 5 character 3/10
<Facility parameter> : : = See Annex G
<Facility request signal> : : = See Annex G
<Full address signal> : : = See Recommendation X.121
<Abbreviated address signal> : : = National option
<Calling line identification signal> : : = See Annex H
<Called line identification signal> : : = See Annex H
<Indicator> : : = See Annexes F and G
<Facility request code> : : = See Annex G
<Registration parameter> : : = See Annex G
<Call progress signal> : : = See Annex F
<DCE–provided information signal>: : = See Annex H
<DTE provided information signal>: : = See Annex F
	The above signals are combined as follows:
<Address signal> : : =	<Full address signal> | < . > <Abbreviated address
signal>	
<Address block> : : =	<Address signal> | <Address block> < , > <Address
signal>	
<Facility registration/cancella-
tion signal> : : =	<Facility request code> </> <Indicator> </>
<Registration parameter> </> <Address signal>	
<Facility registration/cancella-
tion block> : : =	<Facility registration/cancellation signal> | <Facility registration/cancellation block> < , > <Facility regis-tration/cancellation signal>	
<Facility request signal> : : =	<Facility request code> | <Facility request signal> </> <Facility parameter>	
<Facility request block> : : =	<Facility request signal> | <Facility request block>
< , > <Facility request signal>	
<Selection sequence> : : =	<Facility request block> <–> <Address block>
<+> | <Facility request block> <–> <+> |
<Address block> <+> | <Facility registration/cancella-
tion block> <–> <+>	

<Call progress signal> : : =	<Call progress code> | <Call progress code> <–>
<indicator>	
<Call progress block> : : =	<Call progress signal> <+> | <Call progress signal>
< , > <Call progress block>	
<Calling line identification> : : =	<*> <Calling line identification signal> <+>	
<Calling line identification (with DNIC or DCC)> : : =	<**> <Calling line identification signal> <+>	
<Called line identification block> : : =	<Called line identification signal> | <Called line identifi-cation block> < , > <Called line identification signal>	
<Called line identification> : : =	<*> <Called line identification block> <+>	
<Called line identification (with DNIC or DCC)> : : =	<**> <Called line identification block> <+>	
<Dummy line identification> : : =	<*> <+>	
<DCE–provided information block> : : =	<DCE–provided information signal> <+> | <DCE–provided information signal> <,> <DCE–provided information block> (Note)	
<DTE–provided information block> : : =	<DTE–provided information signal> <+> | <DTE–provided information signal> <,> <DTE–provided information block>	
	Note – For DCE–provided information signals and blocks other than calling or called line identification signals and blocks.

ANNEX E
(to Recommendation X.21)
Interworking between DTEs conforming to Recommendations X.21 and X.21 bis
	It is recognized that interworking between V–Series DTEs connected to a public data network according to Recommendation X.21 bis at one end and Recommendation X.21 at the other end should always be possible for DTEs not using half–duplex operation.
	Certain Administrations may provide facilities allowing interworking between DTEs operating in accordance with Recommendations X.21 and X.21 bis using half–duplex operation by switching circuit C, I and circuit 109, 105 during the data transfer phase in accordance with Figure E–1/X.21.
	Those Administrations not providing this facility shall cause the Recommendation X.21 DCE to signal r = 1, i = ON when the Recommendation X.21 bis DTE signals circuit 105 OFF. This will permit half–duplex operation for those DTEs that do not require circuit 109 to be OFF before signalling circuit 105 ON.

FIGURE E-1/X.21	CCITT-25080

ANNEX F
(to Recommendation X.21)
TABLE F–1/X.21
Coding of call progress signals and DTE provided information
Code group
(see Note 1)	 Code	 Indicator	 Significance	 Category	
0	 00 
01
 02
 03 
04 

05	–
–
–
–
–

–	Note 2 
Terminal called
Redirected call
Connect when free
Private network reached
(see Note 3)
Public network reached (see Note 4)	 Without clearing	
2	 20 
21
 22
 23	–
–
–
–	 No connection Number busy  Selection signals procedure error Selection signals transmission error	 With clearing due to short–term conditions	
3				Unassigned	
4 and 5	 41 
42 
43 
44 
45 
45 
46 
47
 48
 49 
51 
52	–
–
–
–
–
YY–MM–DD–hh:mm
–
–
–
–
–
–	Access barred 
Changed number
Not obtainable
Out of order
Controlled not ready
DTE inactive until . . . Uncontrolled not ready DCE power off
Invalid facility request Network fault in local loop Call information service Incompatible user class of service	With clearing due to long–term conditions	
6	 61	 –	 Network congestion	 With clearing due to network short–term conditions	
7	 71 

72	 –
 
–	Long–term network congestion
RPOA out of order	 With clearing due to network long–term conditions	
8	 81 

82 
83	–

–
–	Registration/cancellation confirmed
Redirection activated Redirection deactivated	 With clearing due to network procedure	
9	Reserved for national purposes				

Notes to Table F–1/X.21:
Note 1 – From the DTE point of view group 0 means “wait”, groups 2 and 6 mean “try again, next try may result in a call set–up”, groups 4 and 5, and 7 mean “there is no reason for the DTE to try again because the answer will be the same for a longer period of time”. Since group 8 results from a procedure between the DTE and the network, no special action is expected to be taken by the DTE.
Some Administrations may specify by regulation both the delay between and the maximum number of call re–attempts permitted by a DTE in these circumstances (see Recommendation X.96).
Note 2 – Reserved for use in case of point–to–multipoint calls. This coding is used for a remote DTE to indicate that the call can be established with this one (i.e. no clearing due to the remote DTE or to the network), so that the same order of sequence of call progress signals and called lines identification can be kept.
Note 3 – In the case of sub–addressing, the DTE may see call progress signals which have originated in the public network and/or the private network. In such cases the call progress signal private network reached shall be used to discriminate between the different origins.
Note 4 – In the case of a DTE being connected to a private network which also provides for access to a public network, the DTE may see call progress signals which have originated in the private network and/or the public network. In such cases the call progress signal public network reached should be used by the private network in order to discriminate between the different origins.

ANNEX G
(to Recommendation X.21)
Facility request, indicator and parameter coding
(for use as appropriate in facility request signals and facility registration/cancellation signals)
TABLE G–1/X.21
(see Annex D for formats and Note 1 below)

Facility request code	 Facility parameter	Indicator	Registration 
parameter	Address signal	 Facility	
  0	 –	 –	 –	 –	 Reserved for future use (may be combined with second character)	
  1	 XX 
(see Note 2)	 –	 –	 –	 Closed user group (other than preferential)	
  2	 –	 –	 –	 –	 Unassigned	
  3	 –	 –	 –	 –	 Unassigned	
 45	 –	 1	YY–MM–DD–hh:mm	 –	 DTE inactive registration	
 45	 –	 2	 –	 –	 DTE inactive cancellation	
 50	 –	 –	 –	 –	 Reserved	
 51	 –	 –	 –	 –	 Reserved	
 53	 –	 –	 –	 –	 Reserved	
 60	0, 1, 2, 3, 4, 5	 –	 –	 –	 Multiple address calling	
 61	 –	 –	 –	 –	 Charging information	
 62	 –	 –	 –	 –	 Called line identification	
 63	 –	 1	 –	 –	 Redirection of call activation	
 63	 –	 2	 –	 –	 Redirection of call cancellation	
 63	 –	 3	 –	 –	 Redirection of call status	
 64	 –	 –	 –	 –	 Reverse charging	
 65	 –	 1	 –	 AS	 Direct call registration	
 65	 –	 2	 –	 –	 Direct call cancellation	
 66	 –	 1	 AAS	 AS	 Abbreviated address registration	
 66	 –	 2	 AAS	 –	 Abbreviated address cancellation	
 68	 –	 –	 –	 –	 Reserved	
  7	 –	 –	 –	 –	 Reserved	
  8	 –	 –	 –	 –	 Reserved	
  9	 Reserved for national purposes	
 AAS	abbreviated address signal.
AS	address signal.
Note 1 – For an interim period, the 2/15 “/” separator in the formats will not be used in some networks.
Note 2 – XX is an index number, i.e., a key code for closed user group other than the preferential group. The index number shall be used to distinguish between parts or groups within one facility. The index number shall furthermore be chosen from IA5, column 3, positions 3/0–3/9, giving a range of possible numbers from 00 to 99.

G.1	Multiple address calling
	This facility provides the calling DTE with the capability to request a category of point to multipoint service.
	The coding is as follows:
<60> </> <h> <–> <Address block> <+>
where
	h is a numerical character with the following signficance:
	0 Reserved
	1 Reserved
	2 Reserved
	3 Centralized multipoint
	4 Reserved
	5 Reserved.
G.2	Charging information
	This facility enables the calling DTE to request at the call establishment phase that charging information for the call be provided at the end of the call.
<61> <–> <address> <+>
G.3	Redirection of call
	This facility enables the DTE to request the network to route its incoming calls towards another address. The use of this facility is assigned for an agreed contractual period.
	Activation of redirection of call – The activation of this facility is coded as follows:
<63> </> <1> <–> <+>
	Cancellation of redirection of call – The cancellation of this facility is coded as follows:
<63> </> <2> <–> <+>
	Status of redirection of call – The DTE has the capability to ask the network for the status of its redirection. The coding is as follows:
<63> </> <3> <–> <+>
G.4	Reverse charging
	This facility enables the calling DTE to request that reverse charging be applied for the call.
	The coding is as follows:
<64> <–> <address> <+>
G.5	Direct call on a per call basis
	This facility enables the DTE to designate the address to which all calls will be established when the selection signals phase (state 4) is bypassed during call establishment.
	Registration – The coding of this registration of the address is as follows:
<65> </> <1> </> <0> </> <Address> <–> <+>
where
	<Address> is the designated address.
	The DTE is able to amend the designated address by performing a cancellation procedure followed by the registration procedure.
	The coding of the cancellation procedure is as follows:
<65> </> <2> <–> <+>
G.6	Abbreviated address calling
	This facility enables the DTE to define a full address by an abbreviated address.
	The registration coding of an abbreviated address is as follows:
<66> </> <1> </> <xy> </> <Address> <–> <+>
where
	<xy>	= abbreviated address corresponding to the full address,
	<address>	= full address.
	Cancellation – The coding of the cancellation of an abbreviated address is as follows:
<66> </> <2> </> <xy> <–> <+>
where
	<xy> is the abbreviated address.
G.7	Closed user group selection
	This facility provides the calling DTE with the possibility to communicate within more than one closed user group.
	The coding is as follows:
<1> </> <xx> <–> <Address block> <+>
where
	<xx> is the closed user group index number, i.e. the key code for the closed user group other than the preferential group. The index number shall be used to distinguish between parts or groups within one facility. The index numbers are numerical characters chosen from column 3 of IA5.
G.8	DTE inactive registration/cancellation
	This facility enables the DTE to inform the network about a period of time during which the DTE is unable to accept incoming calls for circuit–switched service.
	DTE inactive registration – The activation of this facility is as follows:
<45> </> <1> </> <YY–MM–DD–hh:mm> <–> <+>
where
	YY: Year, MM: Month, DD: Day, hh: Hour, mm: Minute
	IA5 characters are used for “YY”, “MM”, “DD”, “hh”, “mm”, “–”, and “:”.
	DTE inactive cancellation is as follows:
<45> </> <2> <–> <+>

ANNEX H
(to Recommendation X.21)
Information content of DCE provided information
H.0	General
	Except for the calling and called line identification, the general format for DCE–provided information, as defined in § 4.6.3 should apply.
	The coding of numerical character used to distinguish between different types of DCE–provided information is indicated in Table H–1./X.21.
H.1	Information content of calling and called line identification
	Two formats are defined:
i)	Calling and called line identification consist of the international data number as defined in Recommendation X.121 preceded by two prefixes 2/10 (“ ** ”). In the case where the originating network does not provide calling line identification, only the data network identification code (DNIC) part of the International Data Number preceeded by two prefixes 2/10 (“ ** ”) may be sent in place of the dummy line identification.
ii)	Calling and called line identification consist of the national number (NN) or network terminal number (NTN) preceded by the prefix 2/10 (“ * ”).
H.2	General coding of the DCE–provided information
TABLE H–1/X.21
Coding of DCE provided information
Identifier	 Meaning	 Remarks	
  0	 Reserved		
  1	 Charging information	 See details in § H.3	
  2	 Charging information		
  3	 Charging information		
  4	 Sub–addressing	 See details in § H.4	
  5	 Date and time indication	 See details in § H.5	
  6	 Characteristics of the call	 See details in § H.6	
  7	 Type of call indication	 See details in § H.7	
 81	 Closed user group indication	 See details in § H.8	
 82	 Closed user group outgoing access indication	 See details in § H.8.1	
  9	 Reserved		

H.3	Information content of charging information
	The charging information will inform the subscriber of either the monetary charges for a call, the duration of the call, or the number of units used during the call.
	When charging information is given in monetary charges for the call, n = 1 and the information shall consist of x number of integer digits optionally followed by a colon and two digits representing the fraction. The format applied is as follows:
</> <1> </> <X...>
</> <1> </> <X...> <:> <yy>
	When the charging information is presented as the duration of a call, n = 2 and the information shall consist of x number of integer digits representing seconds, the format applied is as follows:
</> <2> </> <X...>
	When the charging information is presented as the number of units used, n = 3, and the information shall consist of x number of integer digits representing the units, the format applied is as follows:
</> <3> </> <X...>
H.4	Sub–addressing information
	The sub–addressing information will inform the called DTE of the sub–address sent by the calling DTE.
	The format of the sub–addressing information is as follows:
</> <4> </> <X...>
	The format of the dummy information is as follows:
</> <4> </>
H.5	Date and time indication
	The date and time indication will inform the subscriber of the date and time the call is established. The format for the date and time indication is as follows:
</> <5> </> <YY–MM–DD–hh:mm>
where
	YY: Year, MM: Month, DD: day, hh: hour and mm: minute
	IA5 characters are used for “YY”, “MM”, “DD”, “hh”, “mm”, “–” and “:”.
H.6	Characteristics of the call
	The characteristics of the call will inform the called DTE of the different facilities that have been requested by the calling DTE.
	The format of the characteristic of the call is as follows:
</> <6> </> <XY>
where
	X and Y are two numerical characters.

	Table H–2/X.21 indicates the allocation of values of these two characters to facilities.
TABLE H–2/X.21
00	 Reserved	
 01	 Reverse charging	
 02	 Reserved	
 03	 Reserved	
H.7	Type of call indication
	The type of call indication will inform the called DTE of the configuration of the incoming call.
	The format of the type of call indication is as follows:
</> <7> </> <XY>
where
	X and Y are two numerical characters.
	Table H–3/X.21 indicates the allocation of values of those two characters to different configurations of calls.
TABLE H–3/X.21
00	 Reserved	
 01	 Reserved	
 02	 Reserved	
 03	 Centralized multipoint	
 04	 Reserved	
H.8	Closed user group indication
	The closed user group indication will inform the called DTE to which closed user group the incoming call belongs.
	The format of the closed user group indication is as follows:
</> <81> </> <xxxx...x>
where
	<x> : closed user group index number.

H.8.1	Closed user group outgoing access indication
	The closed user group outgoing access indication will inform the called DTE from a DTE belonging to a closed user group with outgoing access facility. If the called DTE belongs to the same closed user group, the local closed user group index number will be indicated. In other cases, no indication will be given.
	The format of the closed user group outgoing access indication is as follows:
</> <82> </> <xx . . . x>
where
	<x> is the closed user group index number.

ANNEX I
(of Recommendation X.21)
Reference and transition tables
TABLE I–1/X.21
Cross reference of interchange circuit signals, states, and reference section
T,	 C	 R,	 I	 State No.	 Reference in the Recommendation (§)	
 1,	 OFF	 1,	 OFF	 1	 2.5.3.1	
 1,	 OFF	 0,	 OFF	 18	 2.5.3.3	
 0,	 OFF	 1,	 OFF	 21, 24	 2.5.3.6	
 0,	 OFF	 0,	 OFF	 17, 20, 22	 2.5.3.4	
 1,	 OFF	 BEL,	 OFF	 8	 4.1.5	
 01,	 OFF	 1,	 OFF	 14	 2.5.3.2	
 01,	 OFF	 0,	 OFF	 23	 2.5.3.5	
 X,	  X	 01,	 OFF	 L27	 7.3.2.8	
 0011,	 OFF	 D,	 ON	 L21	 7.3.2.1	
 0011,	 OFF	 0011,	 OFF	 L22	 7.3.2.2	
 *,	 OFF	 BEL,	 OFF	 9B	 4.1.6.2.2.1	
 *,	 OFF	 IA5,	 OFF	 10C	 4.1.6.2.2.2	
 IA5,	 OFF	 SYN,	 OFF	 25	 4.1.6.2.2.4	
 *,	 OFF	 SYN,	 OFF	 6C	 4.1.6.2.2.3	
 1,	 OFF	 D,	 ON	 13R	 5.2.2, 5.3.1.2, 5.3.2.2	
 0,	 OFF	 1,	 ON	 16	 6.1	
 0,	 OFF	 0,	 ON	 16	 6.1	
 0,	 OFF	 D,	 ON	 16	 6.1	
 1,	 ON	 1,	 OFF	 11	 4.1.10	
 1,	 ON	 0,	 OFF	 19	 6.2	
 0,	 ON	 1,	 OFF	 2	 4.1.1	
 0,	 ON	 0,	 OFF	 19	 6.2	
 1,	 ON	 BEL,	 OFF	 9	 4.1.6	
 1,	 ON	 +,	 OFF	 5	 4.1.4	
 1,	 ON	 SYN,	 OFF	 6A, 6B, 9C	 4.1.7	
 1,	 ON	 IA5, a)	 OFF	 7, 10A, 10B	 4.1.8, 4.1.9	
 0,	 ON	 BEL,	 OFF	 15	 4.3	
 0,	 ON	 +,	 OFF	 3	 4.1.2	
 IA5,	 ON	 +,	 OFF	 4	 4.1.3	
 D,	 ON	 1,	 OFF	 13S	 5.2.1, 5.3.1.1, 5.3.2.1	
D,	 ON	 0,	 OFF	 19	 6.2, Fig. A–3/X.21	
 1,	 ON	 1,	 ON	 12	 4.1.1.1	
 D,	 ON	 D,	 ON	 13	 5.1, 5.2.3, 5.3.3	
a) An IA5 character other than BEL.