YD/T 514-1998Technical requirements and test methods for interface between non-voice subscriber terminal and public telephone network (English PDF)

3.1 Non-voices subscriber terminal

It refers to the telecommunication device connecting to the subscriber line in telephone

network for information communication other than telephone

3.2 Terminals of line A and B

The terminals connecting the non-voices subscriber terminal and the subscriber line of

telephone network

3.3 "On-hook" state

It refers to the working condition that the non-voices subscriber terminal cooperates with

the telephone exchange network. When it is under the "on-hook" state, the non-voices

subscriber terminal produces a high impedance to the telephone network. And it cuts off

the DC circuit, so as to restore the device in local network.

3.4 "Off-hook" state

It refers to another working condition that the non-voices subscriber terminal cooperates

with the telephone exchange network. When it is under the "off-hook" state, the

non-voices subscriber terminal closes the DC circuit, so as to start and maintain the

device's action in local network.

3.5 Longitudinal balance

It is used to measure the balance performance of terminals A and B of the non-voices

subscriber terminal to the ground. The definition formula of longitudinal balance Bm-1 is.

In the formula, Em is called lateral voltage, and it is the potential difference between

terminals A and B. E1 is called longitudinal voltage. It is caused by the unbalance of

terminals A and B to the ground. And it is equal to 1/2 of the vector SUM of the potential

difference of terminal A to the ground AND the potential difference of terminal B to the

ground.

When not sending the dialing signal, the level of each single-frequency signal in dual-tone

multifrequency signal shall not be greater than -70dBm.

4.5 Automatic calling and answering process

The following procedure parameters shall be configured as the default settings of the

device.

4.5.1 Sending conditions of dialing signal

The non-voices subscriber terminal shall wait for at least 2s before sending digital signal

since entering the "off-hook" state.

When a dial tone detection method is adopted, the sending of dialing signal is not

restricted by the above time limit.

4.5.2 Time limit for waiting for answering after dialing

When the non-voices subscriber terminal has not received the answering signals sent by

the opposite terminal after at most 50s from it sending the last dialing signal, it shall cut off

the DC circuit and return to the "on-hook" state.

4.5.3 Interval and times of automatic recalling

Under the conditions of 4.5.2, if there is need to recall this number, it shall wait for at lease

30s from returning to the "on-hook" state before entering into "off-hook" state and recalling.

It shall not recall the same number for more than three times. After 3 times of re-calling,

there shall be at least 5min time interval before recalling this number (except for antitheft,

fire prevention, rescue, and other emergency situations).

4.5.4 Interval time limit for subsequent call

The non-voices subscriber terminal shall enter into the "off-hook" state to call the next

number after at least 5s from it returning to the "on-hook" state.

4.5.5 Response time to ringing

If non-voices service is the key business, it is allowed the non-voice subscriber terminal to

close the DC circuit and enter into the "off-hook" state within 5s from receiving the ringing

signal.

resolution is 1ms, with storage and display functions.

Figure 9 Test connection of dual-tone multifrequency signaling

c) Under the state of not sending signal, use frequency selection level meter to measure

the level value of each signal frequency in the dual-tone multifrequency signals, that is the

signal leakage level value.

d) Let the device under test to send dialing signal continuously, and use storage

oscilloscope to test the continuous time and interval time of the signal.

5.5 Test of electric safety indicator

The test method of electric safety indicator shall comply with the relevant provisions of

YD/T 965.

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