R2511-HP MSR Router Series Voice Configuration Guide(V5)

When the terminating side supports metering signals, the system might send a forced release

signal 00 instead of a clear-back signal 11 to release the line. This is to avoid collision between

the clear-back signal sent by the called party and the metering signal.

5. Blocking in idle state or during conversation.

After the originating side receives a blocking signal 11 from the terminating side when the circuit

is idle or during conversation, it sends a forward signal 10. At this time, the circuit is blocked.

When the terminating side unblocks the circuit, it sends a backward signal 10 in the

corresponding line to indicate that the line is idle. The originating side should maintain the forward

signal 10 and unblock the local-end circuit for next call.

6. Troubleshooting in idle state.

If the terminating side receives a forward signal 11 from the originating side to indicate a device

fault when the circuit is idle, the terminating side sends a backward signal 11. Then, the circuit is

in faulty state. When the device recovers, the originating side sends the forward signal 10, and the

terminating side responds with the signal 10. At this time the circuit regains normal state.

7. Troubleshooting during conversation.

After the terminating side receives a forward signal 11 from the originating side to indicate device

fault during conversation, the terminating side releases the line backward. At the same time, it

sends a backward signal 11. Then, the circuit is in faulty state. When the device recovers, the

originating side sends a forward signal 10, and the terminating side sends back a signal 10. At

this time, the circuit recovers.

ITU-T interregister signaling

Interregister signaling controls automatic connection of circuits. It adopts MFC mode and includes

forward signaling and backward signaling. Forward signaling exchange includes Group I and Group II,

while backward signaling exchange includes Group A and Group B. When the originating side

recognizes the seizure acknowledgement signal, the register begins to send the first digit of the called

number, and waits for the response of Group A signaling from the terminating side.

• Group I forward signals—Include connection control signals and digit signals.

Table 7 Forward Group I signals

Desi

nation Basic meanin

I-1 through I-10

Digits 1, 2, 3, 4, 5, 6, 7, 8, 9, and 0, responsible for sending number

information to the terminating side

I-11 Spare for national use

I-12 Request refused

I-13 Connected to tested device

I-14 Spare for national use

I-15

Address identification terminator and pulse terminator (used in

international calls)

• Group A backward signals—Control signals used for controlling and acknowledging Group I

forward signals.

Table 8 Group A backward signals

Desi

nation Basic Meanin

A-1 Send next digit