/* R2 group I forward signals */
/* The meaning of these signals depends whether they are the first signal on
   an international circuit or not. */
#define R2_SIGI_1   '1'     /* First: Language digit - French */
                            /* Other: Digit 1 */
#define R2_SIGI_2   '2'     /* First: Language digit - English */
                            /* Other: Digit 2 */
#define R2_SIGI_3   '3'     /* First: Language digit - German */
                            /* Other: Digit 3 */
#define R2_SIGI_4   '4'     /* First: Language digit - Russian */
                            /* Other: Digit 4 */
#define R2_SIGI_5   '5'     /* First: Language digit - Spanish */
                            /* Other: Digit 5 */
#define R2_SIGI_6   '6'     /* First: Spare (language digit) */
                            /* Other: Digit 6 */
#define R2_SIGI_7   '7'     /* First: Spare (language digit) */
                            /* Other: Digit 7 */
#define R2_SIGI_8   '8'     /* First: Spare (language digit) */
                            /* Other: Digit 8 */
#define R2_SIGI_9   '9'     /* First: Spare (discriminating digit) */
                            /* Other: Digit 9 */
#define R2_SIGI_10  '0'     /* First: Discriminating digit */
                            /* Other: Digit 0 */
#define R2_SIGI_11  'B'     /* First: Outgoing half echo suppressor required */
                            /* Other: Operator code 11 */
#define R2_SIGI_12  'C'     /* First: No echo suppressor required */
                            /* Other: Operator code 12/request not accepted */
#define R2_SIGI_13  'D'     /* First: Test call indicator (call by ATE) */
                            /* Other: Code 13 (call to ATE) */
#define R2_SIGI_14  'E'     /* First: Incoming half echo suppressor required */
                            /* Other: Incoming half echo suppressor required */
#define R2_SIGI_15  'F'     /* First: Signal not used */
                            /* Other: End of pulsing (code 15) */

/* R2 group II forward signals */
#define R2_SIGII_1  '1'     /* National - subscriber initiated call */
#define R2_SIGII_2  '2'     /* National - subscriber with priority call */
#define R2_SIGII_3  '3'     /* National - maintenance equipment call */
#define R2_SIGII_4  '4'     /* National - spare */
#define R2_SIGII_5  '5'     /* National - operator initiated call */
#define R2_SIGII_6  '6'     /* National - data transmission call */
#define R2_SIGII_7  '7'     /* International - Subscriber (or operator without
                               forward transfer facility) */
#define R2_SIGII_8  '8'     /* International - data transmission call */
#define R2_SIGII_9  '9'     /* International - subscriber with priority */
#define R2_SIGII_10 '0'     /* International - operator with forward transfer
                               facility */
#define R2_SIGII_11 'B'     /* Spare for national use */
#define R2_SIGII_12 'C'     /* Spare for national use */
#define R2_SIGII_13 'D'     /* Spare for national use */
#define R2_SIGII_14 'E'     /* Spare for national use */
#define R2_SIGII_15 'F'     /* Spare for national use */

/* R2 group A backward signals */
#define R2_SIGA_1   '1'     /* Send next digit (DNIS) (n+1) */
#define R2_SIGA_2   '2'     /* Send last but one digit (DNIS) (n-1) */
#define R2_SIGA_3   '3'     /* Address complete. Change to group B signals */
#define R2_SIGA_4   '4'     /* Congestion in national network */
#define R2_SIGA_5   '5'     /* Send calling party's category (+ ANI) */
#define R2_SIGA_6   '6'     /* Address complete. Charge. Set-up speech conditions */
#define R2_SIGA_7   '7'     /* Send last but two digits (DNIS) (n-2) */
#define R2_SIGA_8   '8'     /* Send last but three digits (DNIS) (n-3) */
#define R2_SIGA_9   '9'     /* Spare for national use */
#define R2_SIGA_10  '0'     /* Spare for national use */
#define R2_SIGA_11  'B'     /* Send country code indicator */
#define R2_SIGA_12  'C'     /* Send language or discriminating digit */
#define R2_SIGA_13  'D'     /* Send location of outgoing R2 international register */
#define R2_SIGA_14  'E'     /* Is an incoming half echo suppressor required? */
#define R2_SIGA_15  'F'     /* International exchange congestion */

/* R2 group B backward signals */
#define R2_SIGB_1   '1'     /* Spare for national use */
#define R2_SIGB_2   '2'     /* Subscriber transferred - send SIT to the caller */
#define R2_SIGB_3   '3'     /* Subscriber line busy */
#define R2_SIGB_4   '4'     /* Congestion (encountered after change from
                               group A to group B). */
#define R2_SIGB_5   '5'     /* Unassigned number */
#define R2_SIGB_6   '6'     /* Subscriber line free - charge */
#define R2_SIGB_7   '7'     /* Subscriber line free - no charge */
#define R2_SIGB_8   '8'     /* Subscriber line out of order */
#define R2_SIGB_9   '9'     /* Spare for national use */
#define R2_SIGB_10  '0'     /* Spare for national use */
#define R2_SIGB_11  'B'     /* Spare for national use */
#define R2_SIGB_12  'C'     /* Spare for national use */
#define R2_SIGB_13  'D'     /* Spare for national use */
#define R2_SIGB_14  'E'     /* Spare for national use */
#define R2_SIGB_15  'F'     /* Spare for national use */