PS-SAU-1900E
Mar. 8
th
,1999 (Rev. 0.0)
--- CONFIDENTIAL AND PROPRIETARY ---
12
2.3.1. Functional
Characteristics.
The LIU is the hardware interface between the external analog telephone device and the Qualcomm
MSM controller, which is located in the CDMA Module. The primary requirement of the LIU is to supply
the necessary electrical interface for telephone devices which comply with EIA/TIA-RS-470-A.
There are several important software-driven functions which are critical to the proper operation of the LIU
interface. Most of these functions are associated with the LIU only in that the LIU provides the necessary
signals used by the software to establish hardware timing and control. As consequence, the following
table of Functional Characteristics will include both hardware and software controlled parameters.
Characteristic
Performance Criteria
Hookswitch Transition (On to Off Hook)
Must Acknowledge (Idle): t < 150 ms
Must Acknowledge (Ring Trip): t < 200 ms.
Must Ignore: t <= 25 ms.
Steady State DC level: t < 300 ms
Hookswitch Transition (Off to On Hook)
Must Acknowledge: t >= 1550 ms
Must Ignore: t < 100 ms
Steady State DC Level: t < 300 ms
Hookflash Signal
300 ms <= t <= 1 sec
Dial Tone Delay after Valid Off Hook
detected (assuming Network Accessed).
T
network_Accessed
+ (20 ms <= t <= 300 ms)
NOTE: The value
T
network_Accessed
is system
dependent. The product continuously verifies
network access conditions when powered. If a
valid PILOT signal is present, then
T
network_Accessed
will be very short ( < 300 mS). However, if a valid
PILOT signal is not present when OFF HOOK
occurs, then
T
network_Accessed
is undefined. Fast Busy
will be presented to the analog loop interface.
Detection of Improper Off Hook conditions.
Must be able to detect condition in which loop is
improperly active. Conditions are:
•
a disconnect has been issued by the far end, but
the near end has not gone on hook after a 1
minute time-out.
NOTE: The suggested
handling is to first detect the J-STD-008 Far
End Disconnect signal, then to generate an
800 mS disconnect, and then to re-issue dial
tone.
•
the near end has come off hook, not for the
purpose of receiving a call, and, after a 1 minute
time-out, has not initiated a dialing sequence:
generate ROH tone.
•
the near end has come off hook, initiated, but
failed to complete a dialing sequence after a 1
minute time-out: generate ROH tone.
NOTE:
The LAU should support an optionally
programmable control called AUTO-SEND.
If
AUTO-SEND is set TRUE, then the LAU will
transmit any collected digits to the switch
after a programmed time-out interval.
Improper Loop Termination detection.
No requirement.
