R2 Signaling Tones and Pulse Code Modulation Line Signaling

This chapter describes the R2 signaling tones generated and detected by the MFCR2 transceiver cards, and the R2 pulse code modulation (PCM) 2-bit line signaling transmitted and received by E1 spans.

Forward and Backward Signaling Tones

Table 2-1 through Table 2-4 provide R2 signaling information based on ITU Q.441 as it applies specifically to the Mexico country feature package.

Table 2-1: R2 Signaling Group I Forward Signals

Token Data Field	Designation	Frequencies	Meaning
1	G-I-1	1380 + 1500 Hz	Digit 1
2	G-I-2	1380 + 1620 Hz	Digit 2
3	G-I-3	1500 + 1620 Hz	Digit 3
4	G-I-4	1380 + 1740 Hz	Digit 4
5	G-I-5	1500 + 1740 Hz	Digit 5
6	G-I-6	1620 + 1740 Hz	Digit 6
7	G-I-7	1380 + 1860 Hz	Digit 7
8	G-I-8	1500 + 1860 Hz	Digit 8
9	G-I-9	1620 + 1860 Hz	a) Digit 9 b) Access to long distance system c) Transit indication
10	G-I-10	1740 + 1860 Hz	a) Digit 0 b) Access to special service
11	G-I-11	1380 + 1980 Hz	Not applicable
12	G-I-12	1500 + 1980 Hz	Not applicable
13	G-I-13	1620 + 1980 Hz	Not applicable
14	G-I-14	1749 + 1980 Hz	Not applicable
15	G-I-15	1860 + 1980 Hz	Not applicable

Table 2-2: R2 Signaling Group II Forward Signals

Token Data Field	Designation	Frequencies	Meaning
1	G-II-1	1380 + 1500 Hz	Not applicable
2	G-II-2	1380 + 1620 Hz	Ordinary subscriber without priority
3	G-II-3	1500 + 1620 Hz	Public phone
4	G-II-4	1380 + 1740 Hz	Time and cost
5	G-II-5	1500 + 1740 Hz	Not applicable
6	G-II-6	1620 + 1740 Hz	Not applicable
7	G-II-7	1380 + 1860 Hz	Long distance public phone
8	G-II-8	1500 + 1860 Hz	Not applicable
9	G-II-9	1620 + 1860 Hz	Not applicable
10	G-II-10	1740 + 1860 Hz	Not applicable
11	G-II-11	1380 + 1980 Hz	Not applicable
12	G-II-12	1500 + 1980 Hz	Not applicable
13	G-II-13	1620 + 1980 Hz	Not applicable
14	G-II-14	1740 + 1980 Hz	Not applicable
15	G-II-15	1860 + 1980 Hz	Not applicable

Table 2-3: R2 Signaling Group A Backward Signals

Token Data Field	Designation	Frequencies	Meaning
1	A-1	1140 + 1020 Hz	Send next digit (n+1)
2	A-2	1140 + 900 Hz	Start from first digit
3	A-3	1020 + 900 Hz	Number complete; change over to reception of Group B signals
4	A-4	1140 + 780 Hz	Network congestion
5	A-5	1020 + 780 Hz	Not applicable
6	A-6	900 + 780 Hz	Send Group II signal and change to Group C signals
7	A-7	1140 + 660 Hz	Not applicable
8	A-8	1020 + 660 Hz	Not applicable
9	A-9	900 + 660 Hz	Not applicable
10	A-10	780 + 660 Hz	Not applicable
11	A-11	1140 + 540 Hz	Not applicable
12	A-12	1020 + 540 Hz	Not applicable
13	A-13	900 + 540 Hz	Not applicable
14	A-14	780 + 540 Hz	Not applicable
15	A-15	660 + 540 Hz	Not applicable

Table 2-4: R2 Signaling Group B Backward Signals

Token Data Field	Designation	Frequencies	Meaning
1	B-1	1140 + 1020 Hz	Free with charging
2	B-2	1140 + 900 Hz	Busy
3	B-3	1020 + 900 Hz	Not applicable
4	B-4	1140 + 780 Hz	Blocking
5	B-5	1020 + 780 Hz	Free without charging
6	B-6	900 + 780 Hz	Not applicable
7	B-7	1140 + 660 Hz	Not applicable
8	B-8	1020 + 660 Hz	Not applicable
9	B-9	900 + 660 Hz	Not applicable
10	B-10	780 + 660 Hz	Not applicable
11	B-11	1140 + 540 Hz	Not applicable
12	B-12	1020 + 540 Hz	Not applicable
13	B-13	900 + 540 Hz	Not applicable
14	B-14	780 + 540 Hz	Not applicable
15	B-15	660 + 540 Hz	Not applicable

Table 2-5: R2 Signaling Group C Backward Signals

Token Data Field	Designation	Frequencies	Meaning
1	C-1	1140 + 1020 Hz	Send next number of Subscriber A
2	C-2	1140 + 900 Hz	Send first digit BNUM
3	C-3	1020 + 900 Hz	Send Group II and Group B signals
4	C-4	1140 + 780 Hz	Congestion
5	C-5	1020 + 780 Hz	Send next digit BNUM
6	C-6	900 + 780 Hz	Repeat last digit BNUM
7	C-7	1140 + 660 Hz	Not applicable
8	C-8	1020 + 660 Hz	Not applicable
9	C-9	900 + 660 Hz	Not applicable
10	C-10	780 + 660 Hz	Not applicable
11	C-11	1140 + 540 Hz	Not applicable
12	C-12	1020 + 540 Hz	Not applicable
13	C-13	900 + 540 Hz	Not applicable
14	C-14	780 + 540 Hz	Not applicable
15	C-15	660 + 540 Hz	Not applicable

Pulse Code Modulation Line Signaling

Table 2-6 describes the 2-bit, channel-associated PCM line signaling used by VCO systems equipped with E1 interface cards. Forward signals are used by originating or outgoing ports, while backward signals are generated by incoming ports. For more information on E1 cards, refer to the Cisco VCO/4K Card Technical Descriptions.

Table 2-6: R2 Pulse Code Modulation Line Signaling

Signal	Exchange Signaling
Signal	Forward Af Bf	Backward Ab Bb
Idle	1 0	1 0
Seize	0 0	1 0
Seize acknowledge	0 0	1 1
Clear forward before answer	1 0	1 1
Release guard	1 0	1 0
Seizure acknowledge	0 0	1 1
Answer	0 0	0 1
Clear forward after answer	1 0	0 1
Release guard	1 0	1 0
Clear-back	0 0	1 1
Clear forward after clear-back	1 0	1 1
Release guard	1 0	1 0
Blocking	1 0	1 1
Unblocking	1 0	0 0

Table of Contents

R2 Signaling Tones and Pulse Code Modulation Line Signaling

Forward and Backward Signaling Tones

Pulse Code Modulation Line Signaling