
DS3171/DS3172/DS3173/DS3174 
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8.2 Detailed Pin Descriptions 
Table 8-2. Detailed Pin Descriptions 
n=1,2,3,4 (port number); Ipu (input with pullup), Oz (output tri-stateable) (needs an external pullup or pulldown resistor to keep from floating), Oa 
(Analog output), Ia (analog input), IO (Bidirectional inout); all unused input pins without pullup should be tied low. 
PIN NAME 
TYPE 
PIN DESCRIPTION 
Line IO 
TLCLKn 
O 
Transmit Line Clock Output 
TLCLKn
: This signal is available when the transmit line interface pins are enabled 
(
PORT.CR2.
TLEN). This clock is typically used as the clock reference for the TDATn 
and TNEG signals, but can also be used as the reference for the TSOFIn, TSERn, 
and TSOFOn / TDENn signals. 
This output signal can be inverted. 
o 
DS3: 44.736 MHz +20 ppm 
o 
E3: 34.368 MHz +20 ppm 
Transmit Positive AMI / Data Output 
TPOSn
: When the port line interface is configured for B3ZS, HDB3 or AMI mode and 
the transmit line interface pins are enabled (
PORT.CR2.
TLEN), a high on this pin 
indicates that a positive pulse should be transmitted on the line. The signal is updated 
on the positive clock edge of the referenced clock pin if the clock pin signal is not 
inverted, otherwise it is updated on the falling edge of the clock. The signal is typically 
referenced to the TLCLKn line clock output pins, but it can be referenced to the 
TCLKOn, TCLKIn, RLCLKn or RCLKOn pins. This output signal can be disabled 
when the TX LIU is enabled. 
This output signal can be inverted. 
TDATn
: When the port line interface is configured for UNI mode and the transmit line 
interface pins are enabled (
PORT.CR2.
TLEN), the un-encoded transmit signal is 
output on this pin. The signal is updated on the positive clock edge of the referenced 
clock pin if the clock pin signal is not inverted, otherwise it is updated on the falling 
edge of the clock. The signal is typically referenced to the TLCLK line clock output 
pins, but it can be referenced to the TCLKOn, TCLKIn, RLCLKn or RCLKOn pins 
This output signal can be inverted. 
o 
DS3: 44.736 Mbps +20ppm 
o 
E3: 34.368 Mbps +20ppm 
Transmit Negative AMI / Line OH Mask 
TNEGn
: When the port line is configured for B3ZS, HDB3 or AMI mode and the 
transmit line interface pins are enabled (
PORT.CR2.
TLEN), a high on this pin 
indicates that a negative pulse should be transmitted on the line. The signal is 
updated on the positive clock edge of the referenced clock pin if the clock pin signal is 
not inverted, otherwise it is updated on the falling edge of the clock. The signal is 
typically referenced to the TLCLKn line clock output pins, but it can be referenced to 
the TCLKOn, TCLKIn, RLCLKn or RCLKOn pins. 
This output signal can be inverted. 
o 
DS3: 44.736 Mbps +20ppm 
o 
E3: 34.368 Mbps +20ppm 
Transmit Positive Analog 
TXPn
: This pin and the TXNn pin form a differential AMI output which is coupled to 
the outbound 75  coaxial cable through a 2:1 step-down transformer (
Figure 1-1
). 
This output is enabled when the TX LIU is enabled and the output is enabled to be 
driven. When it is not enabled, it is in a high impedance state. 
o 
DS3: 44.736 Mbps +20ppm 
o 
E3: 34.368 Mbps +20ppm 
Transmit Negative Analog 
TXNn
: This pin and the TXPn pin form a differential AMI output which is coupled to 
the outbound 75  coaxial cable through a 2:1 step-down transformer (
Figure 1-1
). 
TPOSn / 
TDATn 
O 
TNEGn  
O 
TXPn 
Oa 
TXNn 
Oa