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參數(shù)資料
| 型號(hào)： | T7256 |
| 廠商： | Lineage Power |
| 英文描述： | ISDN Transceiver(ISDN收發(fā)器) |
| 中文描述： | 綜合業(yè)務(wù)數(shù)字網(wǎng)收發(fā)器（綜合業(yè)務(wù)數(shù)字網(wǎng)收發(fā)器） |
| 文件頁數(shù)： | 5/36頁 |
| 文件大?。?/td> | 697K |
| 代理商： | T7256 |
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Lucent Technologies Inc.
3
Manual
May 1996
SCNT1 Family Reference Design Board
Hardware User’s Manual
Description
(continued)
Circuits
The following sections discuss the circuits found in
Figure 4.
U-Interface
The U-interface attaches to the board at RJ-45 connec-
tor J1 (see Figure 3). F1 and VR2 provide overcurrent
and overvoltage protection, respectively. These two
devices in combination with transformer T1 provide
protection levels required by FCC Part 68 and
UL* 1950. C16 is a 1.0 μF dc blocking capacitor that is
required per ANSI T1.601, section 7.5.2.3. The 250 V
rating of C16 is governed by the maximum breakdown
voltage of VR2, since the capacitor must not break
down before VR2. The resistance of R13 (21
) and F1
(12
) provide a total line-side resistance of 33
,
which is required when using the Lucent Technologies
2754H2 transformer. An alternate footprint is provided
that accepts the Valor
PT4084 U-interface trans-
former.
When the Valor transformer is used, R13 should be
changed to 18.2
. In general, the total line-side resis-
tance requirement, RL, is determined by the following
equation, where Rp is the primary (device-side) wind-
ing resistance of the U-interface transformer and Rs is
the secondary (line-side) winding resistance of the
transformer.
RL = 58.14 – 2.25 Rp – Rs
* ULis a registered trademark of Underwriters Laboratories, Inc.
Valor is a registered trademark of Valor Electronics, Inc.
On the device side of the U-interface transformer, VR1
provides secondary overvoltage protection of 6.8 V.
Optional capacitors C13 and C14 provide common-
mode noise suppression for applications that are
required to operate in the presence of high common-
mode noise. R8 and R9 provide the necessary external
hybrid resistors.
MLT Circuit
The metallic loop termination (MLT) circuit (U3 and
related components) provides a dc termination for the
loop, per ANSI T1.601, section 7.5. R14 and R15 are
power resistors used to sink current during over-
voltage fault conditions. U2 provides signal isolation
and voltage translation of the signaling pulses used for
NT maintenance modes, per T1.601, section 6.5. The
Lucent Technologies T7234, T7237, and T7256
devices interpret these pulses via an internal ANSI
maintenance state machine, and respond accordingly.
For applications outside North America, the MLT circuit
is not needed and can be disabled by simply removing
U3 from its socket.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| T7234 | ISDN Transceiver(ISDN收發(fā)器) |
| T7237 | ISDN Transceiver(ISDN收發(fā)器) |
| T7264 | U-Interface 2B1Q Transceiver(U接口 2B1Q收發(fā)器) |
| T7264 | T7264 U-Interface 2B1Q Transceiver |
| T7289A | DS1 Line Interface(DS1 線接口) |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| T7256A | 制造商:AGERE 制造商全稱:AGERE 功能描述:Compliance with the New ETSI PSD Requirement |
| T7257 | 制造商:TE Connectivity 功能描述: |
| T-726 | 制造商:RHOMBUS-IND 制造商全稱:Rhombus Industries Inc. 功能描述:ADSL Line Interface Transformers |
| T7263 | 制造商:TE Connectivity 功能描述: |
| T7263A | 制造商:Toshiba America Electronic Components 功能描述:T7263A |
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