![](http://datasheet.mmic.net.cn/330000/PM8315_datasheet_16444435/PM8315_243.png)
STANDARD PRODUCT
PM8315 TEMUX
DATASHEET
PMC-1981125
ISSUE 7
HIGH DENSITY T1/E1 FRAMER WITH
INTEGRATED VT/TU MAPPER AND M13 MUX
PROPRIETARY AND CONFIDENTIAL
228
8
Unused
I
-
I
-
I
-
9
Unused
I
-
I
-
I
-
Transparent VT2/TU12 Mapping
VT2 and TU12 virtual tributaries, TVT2s, are transported across the SBI bus in a
similar manner to the E1 tributary mapping. The TEMUX supports both TVT
modes simultaneously in the SBI DROP bus and is configurable on a per
tributary basis in the SBI ADD bus.
Table 34 shows the transparent structure where “I” is used to indicate information
bytes. There are two options when carrying virtual tributaries on the SBI bus, the
primary difference being how the floating V5 payload is located.
The first option is locked TVT mode which carries the entire VT2/TU12 virtual
tributary indicated by the shaded region in Table 34. The TEMUX supports both
TVT modes simultaneously in the SBI DROP bus and is configurable on a per
tributary basis in the SBI ADD bus.
Locked is used to indicate that the location of the V1,V2 pointer is locked. The
virtual tributary must have a valid V1,V2 pointer to locate the V5 payload. In this
mode the V5 indicator and payload signals, SDV5, SAV5, SDPL and SAPL, are
optionally generated but must be ignored by the receiving device. In locked
mode timing is always sourced by the transmitting side, therefore justification
requests are not used and the SAJUST_REQ signal is ignored. Other than the
V1 and V2 octets which are carrying valid pointers, all octets can carry data in
any format. The location of the V1,V2,V3 and V4 octets is fixed to the locations
shown in Table 34.
The second option is floating TVT mode which carries the payload comprised of
the V5 and I octets within the shaded region of The TEMUX supports both TVT
modes simultaneously in the SBI DROP bus and is configurable on a per
tributary basis in the SBI ADD bus.
Table 34. The TEMUX supports both TVT modes simultaneously in the SBI
DROP bus and is configurable on a per tributary basis in the SBI ADD bus.
In this mode the V1,V2 pointers are still in a fixed location and may be valid but
are ignored by the receiving device. The V5 indicator and payload signals, SDV5,
SAV5, SDPL and SAPL, must be valid and are used to locate the floating
payload. (i.e. SDV5/SAV5 are high during the V5 octet, and SDPL/SAPL are high
during all shaded bytes except the V1/V2/V4 octets and the V3 octet or the octet
after V3 depending on pointer movements.) The justification request signal can