Operational Description
G1 Deactivated
The ISAC-S is not transmitting. No signal is detected on the S/T interface, and no activation
command is received in the C/I channel. EI is output as a response to RST, DIU is output in
the normal deactivated state, and TIM is output as a first step when an activation is requested
from the S/T interface.
G1 INFO1 Detected
An INFO1 is detected on the S/T interface, translated to an "Activation Request Upstream"
indication in the C/I channel. The ISAC-S is waiting for an ARD command, which normally
indicates that the transmission line upstream (usually a two-wire interface) is synchronized.
G2 Pending Activation
As a result of the ARD command, an INFO2 is sent on the S/T interface. INFO3 is not yet
received.
G2 Synchronized
INFO3 was received, INFO2 continues to be transmitted while the ISAC-S waits for a "switch-
through" command AID from the device upstream.
G3 Activated
INFO4 is sent on the S/T interface as a result of the "switch through" command AID: the B and
D channels are transparent. In case of loss of synchronism of the NT receiver, INFO2 is sent.
Lost Framing U
On receiving an RSYD command which usually indicates that synchronization has been lost
on the two-wire interface, the ISAC-S transmits continuous alternating pulses.
G4 Pending deactivation
This state is triggered by a deactivation request DR, and is an unstable state. Indication DIU
(state "G4 unacknowledged") is issued by the ISAC-S when:
– either INFO0 is received during 16 ms
– or an internal timer of 32 ms expires.
G4 Unacknowledged
Final state after a deactivation request. The ISAC-S remains in this state until an
"acknowledgement" to DIU (DID) is issued, without which a new activation is impossible.
Test Mode Continuous Pulses
Continuous alternating pulses are sent.
Test Mode Single Pulses
Single alternating pulses are sent (2-kHz repetition rate).
Semiconductor Group
181
INFINEON [ Infineon ]
