NEC NEAX 2000 - Page 220

DIRECT DIGITAL INTERFACE (DDI)
DTI SPECIFICATIONS
– 200 –
A2195-10
DTI SPECIFICATIONS
Transmission Characteristics
Transmission Characteristics
* AMI : Alternate Mark Inversion
ZCS : Zero Code Suppression
B8ZS: Bipolar Eight Zero Substitution
CHARACTERISTICS 24-CHANNEL 30-CHANNEL
(1) Output
• Line Rate
• Line Code
• Line Impedance
• Pulse Amplitude
(Base to Peak)
• Pulse Width
(2) Input
• Line Rate
• Pulse Amplitude
(Base to Peak)
• Frame Synchroniza-
tion Pattern
• Input Jitter
• Wander
• Cable Length from
PBX to CSU
1.544 Mbps ±50 ppm
AMI with ZCS/B8ZS*
100 ohms
3 volts ±0.6 volts
324 ns ±30 ns
1.544 Mbps ±200 bps (130 ppm)
1.5 volts-3 volts
100011011100
ITU-T Fig. 1/G743
+138U1, –193UI or
–138UI, +193UI
Max. 200 m (655 ft.)
[with 0.6
φ (22 ABAM) twisted-
pair cable]
2.048 Mbps ±50 ppm
HDB3 (High Density Bipolar 3)
75 ohms +100 µH
(Coaxial Cable)
120 ohms-160 µH
(Twisted-Pair Cable)
2.37 volts nominal
(Coaxial Cable)
3 volts nominal
(Twisted-Pair Cable)
244 ns nominal
2.048 Mbps ±50 ppm
1.5 volts-2.7 volts
(Coaxial Cable)
1.5 volts-3.3 volts
(Twisted-Pair Cable)
ITU-T Fig. 1/G743
ITU-T G823
Max. 400 m
(with 0.6
φ twisted-pair cable)