mh89760b Mitel, mh89760b Datasheet - Page 13

• Manufacturer Part Number: mh89760b
• Description: St-bus? Family T1/esf Framer & Interface
• Manufacturer: Mitel

Preliminary Information
DS1 Line Interface
Line Transmitter
The transmit line interface is made up of two open
collector drivers (OUTA and OUTB) that can be
coupled to the line with a center tapped pulse
transformer (see Figure 6). A step function is applied
Extracted
Clock
Received
Data
Transmit
Data
COMPONENT VALUES:
R1 = 150 1% W
C1 = 0.01 F 5% 250V
C2 = 0.47 F 5% 100V
L1 = 33 H 130mA
L2 = 33 H 165 mA
TR1 = 1:1:0.5
TR2 = 1:1:1
*Filtran Ltd.
229 Colonnade Road
Nepean, Ontario
Canada K2E 7K3
613-226-1626
Receiver
Line
MH89760B
Rx
1
4
Filtran* Part # TFS2573
Filtran* Part # TFS2574
+5V
OUTA
OUTB
E1.5o
RxA
RxB
RxT
RxR
V
+12V
Figure 6 - Input/Output Configuration
DD
C2
L2
1:
1:
1:
1:
TR1
TR2
Note: The equalizer has been optimized for 22 gauge ABAM
cable. The exact distances may vary with the type of cable and the
output transformer. Different line length settings may be
required if a transformer other than the Filtran TFS2573 is used.
to the transformer when either of the transistors is
turned on. By operating in the transient portion of the
inductance
transformer produces an almost square pulse. The
capacitor and inductor on the center tap of the
transmit transformer shown in Figure 6 suppress
transients in the 12 volt supply. The series RLC
across the output of the transformer shape the pulse
to meet the AT & T or CCITT pulse templates. A
:0.5
:1
S1
S2
S4
S4
S5
S6
S7
R1
L1
C1
CLOSE
0-150’
OPEN
OPEN
OPEN
OPEN
OPEN
OPEN
response,
Equalizer settings
S1
S2
S3
S4
S5
S6
S7
150-450’
CLOSE
CLOSE
CLOSE
OPEN
OPEN
OPEN
OPEN
the
EIT
EIR
EA
EB
EC
SW
RCLT
RCHT
RCLR
RCHR
Ti
Ri
secondary
MH89761
MH89760B
450-655’
CLOSE
CLOSE
CLOSE
OPEN
OPEN
OPEN
OPEN
TxR
TxT
TL
RL
of
4-67
the