Introduction
About the control signals of each channel and voice signals are transmitted within the transmission channel constituting the circuit or transmitted by a separate channel. One time slot can be used to transmit various line signaling of the relevant channels in the PCM system, and other time slots of the same system are used as a word.
Line Signaling (ABCD)
line signaling is a signaling of the call status on the relay line. It can be divided into the following categories:
DC line signaling
DC line signaling DC polarity flags, representing different signaling meanings. Mainly used between the vertical and horizontal telephone bureaus, between the vertical and horizontal bureau and the Steps Branch, between the Directoral Bureau and the Automatic Long Calendar Bureau and the Artificial Departure Bureau and the Special Service Station.
On the audio cable of the mission network, the local line signaling generally uses DC signaling. Because of its simple structure, it is more economical and convenient. However, if the border is more than the limit of the DC signal transmission, it cannot be used.
Belt (external) single pulse line signaling
When using a frequency division multiplexing transmission system, the band or extracted single pulse line signaling can be used. . The inner single pulse line signaling typically selects 2600 Hz within the audio band because there is less frequency component in the voice of 2600 Hz and the low energy is low. External signaling is transmitted to transmit a signal using a frequency between the two voice bands in the carrier circuit. Generally, single frequency 3825 Hz or 3850 Hz is used.
Due to the narrowing frequency band can be utilized by the extracted signaling, the line signaling generally uses the inner single pulse line signaling.
Digital line signaling mode
When using a PCM device, the line signaling between the bureaus must adopt digital line signaling.
CCITT recommended digital line signaling is used: one is used in a 30/32 PCM system and the other is used in a 24-channel PCM system. The first kind of use in Europe, my country has also used this.
In this signaling mode, the 16-time slot transmitted by the PCM is used to transmit line signaling, and fixedly assigned to each voice.
Since the line signaling is mainly used for monitoring of the call status on the trunk and controlling the call continues. Therefore, line signaling can be transmitted during the entire call.
Trunler signaling
The signal is mainly completed by the transmitting and requesting of the main, called number, calling user category, called user status, and call service category. . The forward signal and the rear signal, the forward signal is also divided into I, II, and the rearward signals A and B are two groups. They are defined as shown in the following table:
Trunarer signal Basic meaning
forward signal
group name Basic meaning capacity
< P> I kA call user category 15kc long-distance continuation category 5
Ke Chang City (city) Continue category 5
digital signal number 0 ~ 9 10
II KD Palematic Call Service Category 6
Backward Signal
Group Name Basic Meaning Capacity
AA Signal Collection Aggregation of state and continuous state confirmation 6
BB signal called user status 6
2.1 forward Group I / P>
forward Group I signal Composed of continuous control signals and digital signals.
a, ka signal
ka signal is a calling user category signal transmitted by the Hair True Bureau or the International Bureau of the Organization, and the KA signal is provided. Fees (regular, immediate, free) and user level (ordinary, priority). The associated combination of these two signals is represented by a bitk code, so the ka signal is a combined category signal. The user level and communication service category information in the KA signal is translated from the origin length to the corresponding KC signal. The meaning is shown in the following table:
ka signal meanings
ka signal encoding signal meanings
1 ordinary, periodic
2 ordinary, user Table, immediately
3 ordinary, printer, immediately
4 alternative
5 ordinary free
6 standby
7 Alternate
8 Prepare period
9 standby
10 priority, free
11 backup
12 Alternate
13 test call
14 standby
15 -
B, KC signal
KC signal is The continuous control signal sent by the long-distance office has functions that guarantee the priority user call, the number of satellite circuit sections. Meaning as shown in the following table:
KC signal meanings
KC signal encoding signal meanings
11 standby
12 Specify circuit call
13 test call
14 Priority call
15 control satellite circuit segment number, indicating a satellite circuit
C, KE signal < / p>
Ke signal is a connection control signal that the terminal long-distance office is forwarded to the terminal mission office and the local office. Meaning as shown in the following table:
ke signal meaning
Ke signal encoding signal meanings
11 Voice mailbox notification user message
12 " T "Test Call
13 Alternate
14 Alternate
15 Voice Mail Unpacking Welcome Notification User Message
D, Digital Signal
Digital signal "0 ~ 9" is used to represent the master, called a user number. In addition, the number "15" signal indicates that the calling user number has been sent.
2.2 After the group A signal
, the group A signal is the mutual control signal of the forward group I signal, and the control and confirmation of the forward Group I signal. The meaning is as shown in the following table:
group A group signal meaning
group A group signal encoding signal meanings
1 a1: Send a number
< P> 2 a2: From the first to initiate3 a3: turn to group B signal
4 a4: Machine branch 塞
5 A5: Number
6 A6: Send KA and calling user Number
2.3 Section II Signal (KD)
KD signal is the origin service category. The meaning is as shown in the following table:
KD signal meanings
KD signal encoding signal meanings
1 long distance call semi-automatic call
2 long distance automatic Call (telephone communication or user fax, user data communication)
3 city phone
4 city users fax or user data communication, priority users
5 Semi-automatic checker number
6 test call
2.4 to B group signal (KB)
KB signal is a signal indicating the status of the called user state , Verify the role of KD signal and control. Meaning as shown in the following table:
KB signal meanings
KB signal encoding signal Meaning
Long-distance Continue or Test Continued (when Kd = 1, 2 or 6 Time) When the public is continued (when kd = 3 or 4)
1 called user idle called user idle, do not control recovery
2 called user "city busy" Alternate
3 is called the user "long busy" backup
4 machine key blessing called the user busy or the machine button congestion
5 called the user empty number Call user empty number
6 alternate called user idle, call control restore
joining the signaling order
joining the signal order according to its carrier transfer The way can be divided into two categories, one is the DEC mode, that is, the decimal pulse coding is used; one is multi-frequency encoding method. Since the latter implements a multi-audio combination encoding, the signaling is implemented, whether it is the capacity of signaling or the reliability of the transfer signaling, there is a large increase. In this way, the most common mode is the MFC mode. Its forward signaling and rear signaling are continuous, and it is proven to each forward signaling. This is also the way of signaling used in my country's jurisprudence signaling. At present, the road signaling used in my country is called China No. 1 Signaling System.
China No. 1 Signaling: As the road signaling. For 30/32 time slots 2048k inter-relay transmission mode, TIMESLOT 16 is used to deliver signaling of its voice channel, the determination signaling is MFC (multi-frequency mutual control, that is, two combinations in six frequencies) A group of codes, a total of 15 forward signaling, using two combinations in four frequencies, a set of coded, a total of 6 rear signaling, the forward refers to the main call to the called transmission, the late point means The called call transmission.), The line signaling A, B, C, D are XX11. R2 Signaling and China No. 1 Signaling Differences in R2 Signature Demanic Signaling Signal Signaling DTMF (Double Volume Multi-Frequency), line signaling A, B, C, D are XX01.
User Signaling and Inter-Bar Signaling
According to the work area of the signaling, the following signaling can be divided into user signaling and local signaling.
Both signaling can also be divided into line signaling and multi-frequency sender signaling. The line signaling is transmitted between the network terminal and the connection monitoring portion or between all service circuits. It is a call to the monitoring signal. The line signaling also has a different way when there are different transmission devices. That is, the route signaling uses DC line signaling when using a solid line or audio cable; when the inter-office trunk uses a PCM system, digital line signaling should be employed. The multi-frequency processor signaling is a signaling that is transmitted between the call creation of the terminal circuit. It is a call to the control signal. Multi-frequency recorder signaling generally adopts end-to-end delivery, but sometimes it can also be used to forward delivery.