E1 R2 Configuration Information

Overview

This page is designed to provide information about the Quintum implementation of E1 R2 signaling. Additionally, we provide links for country-specific settings and the parameters for R2 that we have seen and used with Quintum products in the past.

Country-specific Configurations

The following links provide specific technical details for the countries listed.

CCITT

Algeria

Brazil

China

Colombia

Egypt

Ghana

India

Iraq

Korea

Kuwait

Laos

Mexico

Mongolia

Nigeria

Philippines

Romania

Saudi Arabia

Singapore

Zaire

R2 Description

R2 Signaling is a CAS (Channel-Associated Signaling) protocol that was developed in the 1960s. It is still used today in Europe, Asia, Latin America, and Australia. The R2 signaling specification is fully defined in the International Telecommunications Union Telecommunication Standardization Sector (ITU-T) Recommendations Q.400 through Q.490. This topic does not provide the full definition, but touches on the basics.

Although R2 signaling has been defined, various countries have elected to implement R2 differently. So while some carriers may tell you just to use the CCITT standard, there are many variations to this standard and more specific information may be needed.

There are two elements to R2 Signaling, explained more fully below:

• Line Signaling (supervisory signals)

• Inter-register Signaling (call setup/control signals)

Line Signaling (Supervisory Signals)

For R2 signaling, only the A and B bits are used. The C and D bits are usually set to a specific value that may vary from country to country. The following table shows the R2 Line Signal, transition and direction used on E1 R2 lines. An idle state is shown when A=1 and B=0.

The line signaling is defined with the following types:

• R2-Digital – R2 Line Signaling using ITU-U Q.421. Typically used for PCM systems where A and B bits are used.

• R2-Analog – ITU-U Q.411 standard. Used for carrier systems where a Tone A bit is used.

• R2-Pulse – ITU-U Supplement 7. For systems that use satellite links where a Tone A bit is pulsed.

The Tenor supports the R2 Digital line signaling.

Inter-register Signaling (Call control signals)

In R2 signaling, the exchanges are considered registers and the signaling between these exchanges is called inter-register signaling. Inter-register signaling uses forward and backward in-band multi-frequency (MF) signals in each time slot to transfer called and calling party numbers, as well as the calling party category.

In some countries, they use two-out-of-six in-band dual tone multi-frequency (DTMF) signaling instead of forward and backward in-band MF signals.

MF signals used during the inter-register signaling are divided in forward signal groups (I and II) and backward signal groups (A and B). The inter-register signaling starts after the seizure ack of the line. The diagram and table below show the forward and backward signal information.

Group-I Signals

• Represent the called party number or dialed digits
• DNIS/ANI digits
• I-1 to I-10 are digits 1 to 10
• I-15 is the end of identification

Group-A Signals

• Indicate if the signaling ended or if a particular forward signal is required
• Used to acknowledge and convey signaling information
• A-1 is to send next digit
• A-3 is address complete, change to Group B signals
• A-4 is congestion
• A-5 is to send calling party’s category
• A-6 is address complete, charge, setup, speech conditions

Group-II Signals

• Represent the calling party category
• II-1 is subscriber without priority
• II-2 to II-9 are subscriber with priority
• II-11 to II-15 are spare for national use

Group-B Signals

• Sent by the termination switch to acknowledge a forward signal, or to provide a call charging and called party information
• Used to acknowledge Group-II forward signals. This is always preceded by an address complete signal A-3
• B-3 is subscriber line busy
• B-4 is congestion
• B-5 is unallocated number
• B-6 is subscriber’s line free charge

The following sequence rules are used to identify the signal group.

• The initial signal received by the incoming exchange is a Group I signal.

• The outgoing exchanges consider backward signals as Group A signals.

• The Group A signals received by outgoing exchanges are used to identify whether the next signal is a Group B signal.

• The Group B signals always indicate and end-of-signaling sequence.

There are three types of inter-register signaling, as follows.

• R2-Compelled – When a tone-pair is sent from the switch (forward signal), the tones stay on until the remote end responds/ACK back with a pair of tones that signals the switch to turn off the tones. The tones are compelled to stay on until they are turned off.

• R2-Non-Compelled – The tone-pairs are sent (forward signal), as pulses so they stay on for a short duration. Responses (backward signals) to the switch (Group B) are sent as pulses. There are no Group A signals in non-compelled signaling.

• R2-Semi-Compelled – Forward tone-pairs are sent as compelled. Responses (backward signals) to the switch are sent as pulses. It is the same as compelled, except that the backward signals are pulsed instead of continuous.

Note

Current software on the Tenor only supports MFC (Multi-Frequency Compelled) R2.

CCITT Standard MFC-R2 Signaling Diagram

The following table shows standard R2 signaling for MFC.