Mitel Sx 50 Dpabx Instructions Guide

							Engineering Information 
Output Signaling Parameters 
4.3 
The SX-50 system provides make/break ratios of 60/40 and 66/33 for outpulsing on 
trunks. Table 4-3 lists the Dial Pulse Output characteristics. Table 4-4 lists the DTMF 
Tone limits. 
Table 4-3 Dial Pulse Output Characteristics 
Parameter 
Pulse Rate 
Percent Break Ratio 
Interdigit Time 8+11 pps 
58 - 64% 
700 - 900 ms Value _ I 
Table 4-4 DTMF Tone Limits 
Parameter 
Frequency Deviation 
+l% maximum Value 
Signal Duration 
Interdigit Time Greater than 50 ms 
Greater than 45 ms 
, 
Cycle Time (DTMF digit + interdigit time) Greater than 93 ms 
I 
1 Level, Low Group 
Level, High Group 
Level, DTMF Signal 
1 Level, Third Frequency 1 Greater than -10 dBm 
I 
Greater than -8 dBm 
Less than 0 dBm 
1 At least 40 dB below DTMF signal p-y 
E&M Signaling 
4.4 
E&M signaling is another method of interoffice signaling. It uses &vo signaling leads 
and two or four audio leads. This method of signaling is preferred to 
positive-negative signaling since its operation is not impaired by differences in the 
earth potential. 
The M lead is used for signaling from the trunk circuit; the E lead is used for signaling 
to the trunk circuit. As a result, signals are sent from office A to office B on the M lead 
of the trunk circuit in office A and arrive on the E lead of office B. Similarly, signals are 
sent from office B on the M lead and arrive on the E lead of office A. The E&M leads 
i 
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							Signaling and Supervision 
provide all the supervisory and dial-pulse signaling required between Central Offices; 
the audio leads are used for DTMF signaling and audio communications. 
Terminating Conditions 
4.5 
The SX-50 system provides the following-line and trunk parameters: 
Station Loop - ONS : The loop resistance, including the set, must be less than 600 
ohms. The ONS Line Card provides a constant current of 25 mA when the set is 
off-hook. Maximum station loop length depends on the gauge of wire used. Refer to 
Table 4-5, Station Loop Length Vs Wire Gauge (ONS Line Card). 
Station Loop - OPS: The OPS Line Card operates on loops of up to 2240 ohms to a 
minimum loop current of 16 mA. When the set is off-hook, the OPS Line Card provides 
a constant current of 30 mA if the station loop has less than 1200 ohms resistance, set 
included. Maximum station loop length depends on the gauge of wire used. Refer to 
Table 4-6, Station Loop Length Vs Wire Gauge (OPS Line Card). 
SUPERSET 
and SUPERSET Telephone Loop: The SUPERSET telephone draws 
a current of 30 mA. Maximum station loop length depends on the gauge of wire used. 
Refer to Table 4-7, Station Loop Length Vs Wire Gauge (COV Line Card). 
SUPERSET 
470 and SUPERSET 420 Telephone Loop: The DNIC Line Card 
operates on loop lengths of up to 1000 meters, for wire gauges 19 through 26, and 
provides a current of 30mA. 
CO Trunk Loop: The SX-50 system operates with CO trunks up to a maximum of 1600 
ohms loop resistance. 
CO Trunk Seizure: The SX-50 system maximum seizure dc resistance is 270 ohms 
at 20 mA. 
CO Trunk Resistance: In the idle state, the resistance towards the CO from the trunk 
circuit is no less than 30 Kohms for ground start, and no less than 10 Megohms for loop 
start trunks. 
DID Trunk Loop: The SX-50 system operates with DID trunks of up to 2240 ohms loop 
resistance (minimum 16 mA loop current), CO interface included. The trunk circuit 
provides a constant current of 30 mA if the trunk loop has less than 1200 ohms 
resistance. Maximum trunk loop length depends on the gauge of wire used. Refer to 
Table 4-8, DID Trunk Loop Length Vs Wire Gauge (DID Trunk Card). 
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							Engineering information 
loop Lengths 
Table 4-5 Station Loop Length vs Wire Gauge (ONS Line Card) 
Wire Gauge 
19 
20 
22 
24 
26 
Mix. Station Loop Length 
9,163 m (30,000 feet) 
7,317 m (24,000 feet) 
4,576 m (15,000 feet) 
2,896 m (9,500 feet) _ 
1,829 m (6,000 feet) 
Table 4-6 Station Loop Length vs Wire Gauge (OPS Line Card) 
I Wire Gauge 
I Max. Station Loop Length 
I 
19 37.5 Km (122,900 feet) 
20 29.6 Km (97,100 feet) 
22 18.5 Km (60,700 feet) 
24 11.5 Km (37,800 feet) 
26 7.2 Km (23,700 feet) 
I I Table 4-7 SUPERSET Loop Length vs Wire Gauge (COV Line Card) 
Wire Gauge 
I Max. SUPERSET Loop Length 
I 
19 
20 
22 
24 
26 701 m (2,300 feet) 
549 m (1,800 feet) 
367 m (1,200 feet) 
229 m (750 feet) 
152 m (500 feet) 
Table 4-8 DID Trunk Loop Length vs Wire Gauge (DID Trunk Card) 
Wire Gauge Max. 
SUPERSET Loop Length 
19 41,118 m (134,900 feet) 
20 32,492 m (106,600 feet) 
22 20,330 m (66,700 feet) 
24 12,649 m (41,500 feet) 
26 7,925 m (26,000 feet) 
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							Signaling and Supervision 
Ringing Generator 
4.6 The ringing generator can ring nine circuits simultaneously. However, 
time-division-multiplexing of the ringing signal actually allows 27 circuits to be in the 
ringing state at any time. A maximum of five ringing devices can be connected to 
each circuit. Table 4-9 lists the ringing generator output parameters. 
Table 4-9 Ringing Generator Parameters 
Parameter 
Frequency 120Hz 
Frequency Drift (for any input, output or 
temperature variation) Less than 1 Hz 
Voltage 
Waveshape 75 Vrms +5 V 
Sinusoidal with less than 5% distortion super- 
imposed on -48 Vdc 
Time-out Periods 
4.7 Table 4-10 lists the time-out periods for the SX-50 system. 
Table 4-10 Time-Out information 
Time-Out Type Quantity 
Attendant-Timed Recall (Don’t Answer) 
(1+7)xlOs 
Attendant-Timed Recall (Camp-on) 
(l+-7)xlOs 
Attendant-Timed Recall (Call Hold) 
I(1 -7)xlOs 
Automatic Switching to Night Bell 
Callback Clear Time-out Immediate OR (1 - 7) x 10 s 
8 hours OR 4 rings 
Call Hold Recall (Station) 
Dial Tone Time-out 1 - 4 minutes 
10s 
Interdigit Time-out 10s 
Lockout Time-out 110s 
Ringing Time-out 5 - 5.5 minutes 
Switchhook Flash 
Tip-Ground CO Acknowledgement 140 ms minimum 
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							5 
’ TRANiMlSSlON 
Transmission Characteristics 
5.1 The insertion loss at 1004 Hz is as follows: 
l Station-t-Station connection: 6 dB kO.5 dB 
l Station-to-Trunk connection: 0.0 dB kO.5 dB. 
_ t 
Table 5-l Attenuation Variation 
Frequency or 
Attenuation Variation 
Transmission Plan Frequency Band (Hz) 
w/r to 1004 Hz (dB) 
Line to Line 200 0. 0 to +2.5 
300 to 3000 -0. 25 to +0.5 
3200 -0. 3 to +0.7 
Line to Trunk 200 0. 0 to +2.5 
300 to 3000 -0. 25 to +0.5 
3200 -0. 3 to +0.7 
Note: (+) is more loss, (-) is less loss. 
The attenuation variation, relative to the 1004 Hz insertion loss, does not exceed the 
limits as shown in Table 5-1. 
Distortion 
5.2 The second or third harmonic does not exceed a level of -55 dBm with a 200 or 1004 
Hz signal at -10 dBm. With an input signal consisting of 900 Hz and 1004 Hz (each at 
-13 dBm), the RMS sum of all the intermodulation products does not exceed -45 
dBm when measured at the output. 
Overload 
5.3 The change in attenuation when the input level of a 1004 Hz signal exceeds 0 dBm is 
as follows: 
Change in signal level Output increase 
from 0 dBm to +3 dBm < 0.1 dB 
from +3 dBm to +5 dBm < 1 .O dB 
from +5 dBm to +7 dBm < 3.0 dB 
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							Engineering Information 
Return Loss 
5.4 The Return Loss parameters in the talking state, Station-to-Station or 
Station-to-Trunk, are: 
ERL (Echo Return Loss) >I8 
dB SRL (Singing Return Loss) >12 dl3 
Longitudinal Balance 
5.5 All connections meet the following requirements with respect to longitudinal,balance: 
Minimum 
200 Hz 
58 dB 1000 Hz 
58 dB Maximum 
3000 Hz 
54 dB 
Crosstalk Attenuation 
5.6 The minimum crosstalk attenuation between any two established connections 
through the DPABX when both paths are correctly terminated is -70 dB. For at least 
95% of all connections through the DPABX, minimum crosstalk attenuation will be 
-75 dB. These figures are based on a disturbing signal at 0 dBm and an applicable 
frequency range of 200 to 3400 Hz. . 
Message Circuit Noise 
5.7 The total level of all noise sources within the system does not exceed the following 
limits (on 95% of the connections): 
l Station-to-Station - 

						

							Transmission 
System Impedance 
5.8 System impedances are: 
l 600 ohms nominal for Stations 
l 600 ohms nominal for Trunks with selectable Balance Impedance of 600 ohms or 
Complex Impedance (350 Q plus 1000 Q in parallel with 0.21 pF). 
Envelope Delay 
5.9 The maximum envelope delay, Station-to-Station or Station&-Trunk, is: 
515 ys between 400 Hz and 600 Hz, 
320 us between 600 Hz and 1000 Hz, 
150 t~s between 1000 Hz and 2600 Hz, 
320 ps between 2600 Hz and 3000 Hz, 
515 ps between 3000 Hz and 3200 Hz. 
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							6 
’ LINE CARD OPERATION 
ONS/OPS Line Card Operation 
6.1 When a telephone goes off-hook, the line circuit detects the flow of loop current and 
signals the Main Processor on the Control Card. The processor responds by 
connecting a DTMF receiver to the line and sending dial tone to the set. (If the set 
uses pulse dialing, then the processor detects the pulses. by monitoring the loop 
current). The user can then dial the desired number. 
When a call is directed to a station, the system applies ringing voltage to the appropriate 
line and monitors the loop current for an off-hook condition. When the telephone is 
answered, the ringing voltage is removed. 
When a call is ended by one of the sets going on-hook, the call is disconnected and 
the line returns to the idle state. 
COV Line Card Operation 
6.2 Control information from the Control Card is converted to a 32 KHz Amplitude Shift 
Keyed (ASK) data stream. The audio information is acquired in PCM form from the 2 
MBit/s data link, converted to analog audio and combined with the control information 
for transmission to the set. Conversely, the audio and ASK data signals from the set 
are separated and converted. The ASK data is demodulated and sent to the 
processor. The audio is converted to PCM and transmitted on the data link. 
There is only one UART and one modem on the COV Line Card. The eight lines are 
time-division-multiplexed to the communication circuit. Transmission and reception 
are sequential, but the card receives data from the set to which it last transmitted. For 
example, the card receives from set A and then transmits to set B. In the next time slot 
it receives from set B and transmits to set C. 
DNIC Line Card Operation 
I 
6.3 Digital Network Interface Circuit (DNIC) Line Card communicates with a 
DNIC-equipped device using digital transmission techniques; a voice channel, data 
channel and control channel. It allows simultaneous transmission of voice and data 
over a single twisted pair of wires. When the DNIC line’card is connected to 
SUPERSET 470 and SUPERSET 420 telephones, each telephone may be 
connected to a MILINK’” Data Module which can be connected to a personal 
computer, or similar data device. The voice operation of the telephone and data 
operation of the data device can function concurrently. 
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