
PEB 80900
Part II
’
IEC-T
’
: Functional Description
Data Sheet
97
2001-04-02
6.4
Synchronous and Deactivated States of the Module Interface
Depending on the application, two different cases have to be distinguished:
In the repeater (NT-RP or LT-RP) modes and in the NT and TE modes, the module
interface will be switched to power-down in the deactivated state. This means that the
clocks are stopped. This is necessary to reduce power consumption in case of remote
power supply. Depending on the direction of the clock signals, the NTC-T AM with
IEC-T functionality selected in NT, NT-RP, and NT-TE modes serves as upstream unit
while the NTC-T AM with IEC-T functionality selected in LT-RP mode serves as a
downstream unit.
In the exchange (LT or LT-BURST) modes and TMD (NT-PABX or NT-PABX-BURST)
modes, the interface remains in the synchronous state. In this case, commands may
also be given to the NTC-T AM with IEC-T functionality selected in the power-down
state. A low power consumption is not very important in these applications.
6.4.1
Deactivation of the IOM
- interface is controlled solely through the upstream unit. Such
deactivation occurs whenever the corresponding Uk0 interface is deactivated.
The corresponding procedure is shown in the following figure. The upstream unit starts
by transmitting the DR command in the C/I channel. After detecting the code DIU from
the downstream unit, the upstream unit responds by transmitting the DID command
during subsequent frames and stops the timing signals at the end of bit A4 of the 4
th
frame. In the power-down state, both of the data lines are logically high and the timing
signals CLOCK and FRAME are logically low. The voltage of the CLS clock may be high
or low.
The downstream unit may be powered down after detection of code DID during two
subsequent frames. When the IOM
-interface enters the power-down state, the
downstream unit must also have entered its power-down state.
Transition from Synchronous to Power-Down State