
DS26518 8-Port T1/E1/J1 Transceiver 
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8. 
PIN DESCRIPTIONS 
8.1 
Pin Functional Description 
Table 8-1. Detailed Pin Descriptions 
NAME 
PIN 
TYPE 
FUNCTION 
ANALOG TRANSMIT 
Transmit Bipolar Tip for Transceiver 1 to 8. 
These pins are differential line 
driver tip outputs. These pins can be high impedance if: 
If TXENABLE is low, TTIPn/TRINGn will be high impedance. Note that if 
TXENABLE is low, the register settings for control of TTIPn/TRINGn are ignored 
and output is high impedance. 
The differential outputs of TTIPn and TRINGn can provide internal matched 
impedance for E1 75
Ω
, E1 120
Ω
, T1 100
Ω
, or J1 110
Ω
. The user can turn off 
internal termination. 
Note: 
The two pins shown for each transmit bipolar tip (e.g., pins A1 and A2 for 
TTIP1) should be tied together.
Transmit Bipolar Ring for Transceiver 1 to 8. 
These pins are differential line 
driver ring outputs. These pins can be high impedance if: 
If TXENABLE is low, TTIPn/TRINGn will be high impedance. Note that if 
TXENABLE is low, the register settings for control of TTIPn/TRINGn are ignored 
and output is high impedance. 
The differential outputs of TTIPn and TRINGn can provide internal matched 
impedance for E1 75
Ω
, E1 120
Ω
, T1 100
Ω
, or J1 110
Ω
. The user can turn off 
internal termination. 
Note: 
The two pins shown for each transmit bipolar ring (e.g., pins A3 and B3 for 
TRING1) should be tied together. 
Transmit Enable. 
If this pin is pulled low, all transmitter outputs (TTIPn and 
TRINGn) are high impedance. The register settings for tri-state control of 
TTIPn/TRINGn are ignored if TXENABLE is low. If TXENABLE is high, the 
particular driver can be tri-stated by the register settings. 
TTIP1 
TTIP2 
TTIP3 
TTIP4 
TTIP5 
TTIP6 
TTIP7 
TTIP8 
TRING1 
TRING2 
TRING3 
TRING4 
TRING5 
TRING6 
TRING7 
TRING8 
A1, A2 
H1, H2 
J1 J2 
T1, T2 
T15, T16 
J15, J16 
H15, H16 
A15, A16 
A3, B3 
G3, H3 
J3, K3 
R3, T3 
R14,T14 
J14, K14 
G14, H14 
A14, B14 
Analog 
Output, 
High 
Impedance 
Analog 
Output, 
High 
Impedance 
TXENABLE/ 
SCAN_EN 
L13 
Input 
Scan Enable. 
When low, device is in normal operation. Scan enable is selected 
by the SCANMODE pin. 
Note:
 User should not select scan enable—test mode 
only.
ANALOG RECEIVE 
RTIP1 
RTIP2 
RTIP3 
RTIP4 
RTIP5 
RTIP6 
RTIP7 
RTIP8 
RRING1 
RRING2 
RRING3 
RRING4 
RRING5 
RRING6 
RRING7 
RRING8 
C1 
F1 
L1 
P1 
P16 
L16 
F16 
C16 
C2 
F2 
L2 
P2 
P15 
L15 
F15 
C15 
Analog 
Input 
Receive Bipolar Tip for Transceiver 1 to 8. 
The differential inputs of RTIPn 
and RRINGn can provide internal matched impedance for E1 75
Ω
, E1 120
Ω
, T1 
100
Ω
, or J1 110
Ω
. The user can turn off internal termination via the LIU Receive 
Impedance and Sensitivity Monitor register (
LRISMR
). 
Analog 
Input 
Receive Bipolar Ring for Transceiver 1 to 8. 
The differential inputs of RTIPn 
and RRINGn can provide internal matched impedance for E1 75
Ω
, E1 120
Ω
, T1 
100
Ω
, or J1 110
Ω
. The user has the option of turning off internal termination via 
the LIU Receive Impedance and Sensitivity Monitor register (
LRISMR
). 
RESREF 
J5 
Input 
Resistor Reference. 
This pin is used to calibrate the internal impedance match 
resistors of the receive LIUs. This pin should be tied to V
SS
 through a 10k
Ω
±
1% 
resistor.