CN8380 Datasheet, PDF (38/91 Pages) Conexant Systems, Inc – integrated quad line interface unit unit for both 1.544 Mbps (T1) and 2.048 Mbps (E1) applications

2.0 Circuit Description
2.4 Transmitter
CN8380
Quad T1/E1 Line Interface
Option A
Option A uses the standard 1:2 transformer, no series protection resistors (Rs),
and no parallel termination (Rt) for T1 applications. In E1 applications, Rt is
included because it is usually required to provide a minimal level of line
impedance matching.
Table 2-4. Transmit Termination Option A
Application
Series Resistors
(Rs)
Parallel Termination
(Rt, Ω)
Return Loss
(dB)
T1—DSX-1
None
None
0
E1—75 Ω
None
126.4
–10
E1—120 Ω
None
204.4
–10
T1— I.431
None
None
0
NOTE(S):
1. Standard Transformer (1:2 turns ratio)
2. Hardware Mode: HTERM=0
3. Host Mode: ALT_TR = 0, TERM = 0, T_BOOST = 0 [TLIU_CR; addr n2]
Option B
Option B uses the standard 1:2 transformer and no series protection resistors (Rs).
A common parallel termination (Rt) for both T1 and E1 applications is included
to provide line impedance matching.
Table 2-5. Transmit Termination Option B
Application
Series Resistors
(Rs)
Parallel Termination
(Rt, Ω)
Return Loss
(dB)
T1—DSX-1
None
23.7
–30
E1—75 Ω
None
23.7
–18
E1—120 Ω
None
23.7
–18
T1— I.431
None
23.7
–30
NOTE(S):
1. Standard Transformer (1:2 turns ratio)
2. Hardware Mode: Not applicable
3. Host Mode: ALT_TR = 0, TERM = 1, T_BOOST = 0 [TLIU_CR; addr n2]
2-16
Conexant
N8380DSA
Advance Information