
Advisory
September 1997
T7234/T7237/T7256
Data Sheet Advisory
(Refer to the T7234/T7237/T7256 ISDN Transceiver Data Sheets: DS96-041ISDN, DS96-095ISDN, and
DS96-097ISDN.)
In 1996, the European Telecommunications Standards Institute (ETSI) added a micro interruption immunity
requirement to ETR 080 (Sections 5.4.5 and 6.2.5).
Section 5.4.5 in ETSI ETR 080 states the following:
I
A micro interruption is a temporary line interruption due to external mechanical activity on the copper wires
constituting the transmission path.
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The effect of a micro interruption on the transmission system can be a failure of the digital transmission link.
I
The objective of this requirement is that the presence of a micro interruption of specified maximum length
shall not deactivate the system, and the system shall activate if it has deactivated due to longer interruption.
Section 6.2.5 in ETSI ETR 080 states that:
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A system shall tolerate a micro interruption up to t = 5 ms, when simulated with a repetition interval of
t = 5 ms.
Since this is a new requirement, implementers are allowed until the end of 1997 to adhere to this requirement.
The SCNT1 family of U-interface transceivers was upgraded to fully comply with this standard. The devices
have been given an A suffix (T7234A, T7237A, and T7256A).
A proposal was added to the Living List (which is intended to collect issues and observations for a possible
future update of ETSI ETR 080) to change the value of the micro interruption from 5 ms to 10 ms. The current
SCNT1 family of U-interface transceivers (T7234A/T7237A/T7256A) from Lucent Technologies Microelectron-
ics Group meets and exceeds this new requirement.
The above change to the SCNT1 family of transceivers has been fully verified, and test reports are available
upon request.
Ordering Information
Device Code
T7234A- -ML-D
T7234A- -ML-DT
T7237A- -ML-D
T7237A- -ML-DT
T7256A- -ML-D
T7256A- -ML-DT
Shipping Method
Dry Pack—Sticks
Dry Pack—Tape & Reel
Dry Pack—Sticks
Dry Pack—Tape & Reel
Dry Pack—Sticks
Dry Pack—Tape & Reel
Package
44-Pin PLCC
44-Pin PLCC
44-Pin PLCC
44-Pin PLCC
44-Pin PLCC
44-Pin PLCC
Temperature
–40
°
C to +85
–40
°
C to +85
–40
°
C to +85
–40
°
C to +85
–40
°
C to +85
–40
°
C to +85
Comcode
108051814
108050816
108100678
108101908
107997413
108051806
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°
°
°
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°
C
C
C
C
C
C