PXB4219E Datasheet, PDF (63/290 Pages) Infineon Technologies AG – Interworking Element for 8 E1/T1 Lines

IWE8, V3.4
PXB 4219E, PXB 4220E, PXB 4221E
Operational Description
• In “Inactive” mode, no cells are accepted from the “UTOPIA Transmit interface”, and
byte-pattern 0 is sent to the framer transmit interface.
• In “Standby” mode, cells are accepted from the “UTOPIA Transmit interface”, but byte-
pattern 0 is sent to the framer transmit interface.
• In “Active” mode, cells are accepted from the “UTOPIA Transmit interface”, and user
data octets are sent to the framer transmit interface.
When activating the AAL reassembly channels, it is important to follow the initialization
sequence as shown in Table 19. Step 2 must be held at least 250 µs to internally reset
the AAL channel. During this time the device connected to the Framer Transmit Interface
has to be in normal operation allowing the IWE8 to synchronize itself on the frame pulse.
Table 19 Activation sequence for AAL reassembly channels
Step pcfN.
p_tx_act
AAL Transmit Reference Slot.
channel_mode
Minimum Time
1
0 = inactive
00 = Inactive
2
1 = active
00 = Inactive
250 µs
3
1 = active
01 or 11 = Active
4.4.2.2 Physical Reassembly Buffer Size
Based on the cell filling level, AAL type and use of SDT, a memory block can be divided
into subblocks, where the user data octets of a single cell are stored. The size of the
memory subblock per Reassembly Buffer is automatically adapted. Table 20 shows this
relationship.
Table 20
Cell Filling
AAL0
(octets)
33–48
17–32
9–16
4–8
Relationship betw. Cell Filling and Reassembly Buffer Subblock
Size
Cell Filling
AAL1, no
SDT
(octets)
Cell Filling
AAL1, with
SDT
(octets)
Octets per
block
Cells per
block
Octets per
cell
32–47
31–47
64
1
64
16–31
15–30
64
2
32
8–15
7–14
64
4
16
4–7
4–6
64
8
8
The physical Reassembly Buffer size used for a N x 64 kbit/s connection is given by:
Physical Size(octets) = N x 8 x Cell Filling x Cells per Block.
[3]
Data Sheet
63
2003-01-20