T7256 Agere Systems, T7256 Datasheet - Page 10

• Manufacturer Part Number: T7256
• Description: (T7234 - T7256) Compliance
• Manufacturer: Agere Systems

T7234 Single-Chip NT1 (SCNT1) Euro-LITE Transceiver
Pin Information
Table 1. Pin Descriptions (continued)
* I
6
22, 33,
39, 42
u
Pin
= input with internal pull-up; I
11
12
14
15
17
18
19
20
21
23
24
8
9
SYN8K_CTL
ACTMODE
AUTOACT
Symbol
GND
PS2E
PS1E
V
V
TNR
TPR
NC
NC
X1
X2
DDO
DDA
O
(continued)
Type*
d
—
—
—
—
—
O
O
O
I
I
I
I
I
d
d
u
d
d
I
= input with internal pull-down.
Power Status #2. This is an input for the PS2 bit in transmit U-interface data
stream. If the PS2E functionality is not used, this input must be pulled up externally
with a 10 k or less resistor to set the U-interface PS2 bit to the inactive state. An
internal 100 k pull-down resistor is on this pin.
Power Status #1. This is an input for the PS2 bit in transmit U-interface data
stream. If the PS1E functionality is not used, this input must be pulled up externally
with a 10 k or less resistor to set the U-interface PS1 bit to the inactive state. An
internal 100 k pull-down resistor is on this pin.
ACT Bit Mode.
Synchronous 8 kHz Clock Control. If pin is held low during an external RESET,
the SYN8K/LBIND pin performs the SYN8K function. If held high during an external
RESET, the pin performs the LBIND function. An internal 100 k pull-down resistor
is on this pin.
No Connect.
Automatic Activation. If this pin is held low during an external RESET, the AUTO-
ACT bit is written to 0, creating an activation attempt. If pin is held high during ex-
ternal RESET, no activation is attempted. An internal 100 k pull-down resistor is
on this pin.
No Connect.
Crystal Oscillator Ground. Ground lead for crystal oscillator.
Crystal Oscillator Power. Power supply lead for crystal oscillator.
Crystal #1. Crystal connection #1 for 15.36 MHz oscillator.
Crystal #2. Crystal connection #2 for 15.36 MHz oscillator.
Analog Power. 5 V
Transmit Negative Rail for S/T-Interface. Negative output of S/T-interface analog
transmitter. Connect to transformer through a 121
Transmit Positive Rail for S/T-Interface. Positive output of S/T-interface analog
transmitter. Connect to transformer through a 121
0—act = 0 during loopback 2 (per ANSI T1.601). The data received at the NT is
1—act = 1 during loopback 2 after INFO 3 is recognized at the S/T-interface (per
looped back towards the LT as soon as the 2B+D loopback is enabled.
ETR 080). The data received by the NT is not looped back towards the LT until
after ACT = 1 is received from the LT. Prior to this time, 2B+D data toward the
LT is all 1s.
5% power supply leads for analog circuitry.
Name/Function
1% resistor.
1% resistor.
Lucent Technologies Inc.
February 1998
Data Sheet