PXB4221 Infineon Technologies AG, PXB4221 Datasheet - Page 59

• Manufacturer Part Number: PXB4221
• Description: IWE8 Interworking Element for 8 E1/T1 Lines
• Manufacturer: Infineon Technologies AG

Table 17
ATM Adaptation
Layer Type
AAL0
AAL1
AAL1 with CAS
1)
2)
4.3.2
In “Inactive” mode, no data is accepted from the framer receive interface.
In “Active” mode, data is accepted from the framer receive interface, segmented and
cells are written into the Segmentation Buffers and the Output Queue.
In “Standby” mode, data is accepted from the framer receive interface but no cells are
written in the Segmentation Buffers.
In “Substitute” mode, data is accepted from the framer receive interface, but substituted
by a programmable byte-pattern selected by “subst_bpslct” in the “AAL Receive
Reference Slot”. Cells are written into the Segmentation Buffers and the Output Queue.
This mode can be used for trunc conditioning to indicate idle (bit pattern = Ox7F) or out-
of-service conditions (bit pattern = Ox1A) according to af-vtoa-0078 [10] and TR-NWT-
000170 [14]
When activating the AAL segmentation channels, it is important to follow the initialization
sequence as shown in
the AAL channel. During this time the device connected to the Framer Receive Interface
has to be in normal operation allowing the IWE8 to synchronize itself on the frame pulse.
Table 18
Step
1
2
3
The RTS value stored in the RTS buffer of the port is loaded from the Internal Clock
Recovery Circuit ICRC or from the Clock Recovery Interface. A new value will be
Data Sheet
P format, cell may have only 46 user data octets in non-P format
Cb: Required bytes for the CAS subblock in an ATM cell = RoundUp(N/2)
pcfN
p_rx_act
0 = inactive
1 = active
1 = active
Setup of AAL Segmentation Channels
Cell Filling level values
Activation sequence for AAL segmentation channels
Table
Minimum
4
4
4+Cb
AAL Receive Reference Slot.
channel_mode
00 = Inactive
00 = Inactive
01 or 11 = Active
18. Step 2 must be held at least 250 s to internally reset
2)
Partially Filled
Maximum
47
46
46
59
PXB4219 / PXB4220 / PXB4221
Completely Filled
48
47
47
1)
1)
Operational Description
Minimum Time
250 s
2002-05-06