Note:
-
VT-GRP:
In order to carried a mixed size of VTs in a STS-1 SPE in an efficient manner, VT Group (VTG) is defined. The size
of the VTG is 12 columns which is the least common multiple of the four sizes of VTs. Only one type of VT can be contained
within each VTG. Therefore, a VTG can be formed by byte interleave multiplexing 3 VT-2s and 4 VT-1.5s
-
VT-1.5
:Each VT 1.5 frame consists of 27 bytes (3 columns of 9 bytes). These bytes provide a transport capacity of 1.728
Mbps, and thus, can accommodate the transport of a DS1 signal. 28 VT 1.5s may be multiplexed into the STS-1 SPE.
-
VT-2
:Each VT-2 frame consists of 36 bytes (4 columns of 9 bytes). These bytes provide a transport capacity of 2.304 Mbps,
can accommodate the transport one E1 signal. 21 VT-2s may be multiplexed into the STS-1 SPE.
The tributary numbering used above is per Bellcore GR.253/ANSI T1.105 standard.
7.4.4 TX Setup > Payload
Tapping the Tx Payload box opens the Tx Payload Setup screen.
RATE:
Depends on mapping selected;
In VT-1.5 mapping mode, The Low Rate options are 1.544M or Fractional DS1 (Nx64 or Nx56) where;
- 1.544 M: Configures the transmitter for full rate testing at 1.544Mbit/s
- Fractional DS1 (Nx64 or Nx56) : Configures the transmitter for fractional testing using N or M 64kbit/s timeslots. (Contiguous or
non-Contiguous timeslots).
In STS-1 mapping mode/Tributary set to DS3, the Low Rate option are 45M or 1.544M Mux (DS3/DS1 Mux) or Fractional DS1
(Nx64 or Nx56) Mux where;
- 45 M: Configures the transmitter for full rate testing at 45Mbit/s
- 1.544 M Mux mode: Configures the transmitter for full rate testing at 45Mbit/s signal with DS1 payloads( 1 to 28 channels )
- Fractional DS1 Mux mode: Configures the transmitter for full rate testing at 45Mbit/s signal with DS1 payloads( 1 to 28
channels ) for fractional testing using N or M 64kbit/s or 56kbit/s timeslots. (Contiguous or non-Contiguous timeslots).
In VT-2 mapping mode, the Low Rate options are 2M or Fractional E1 (N x64) where;
- 2M: Configures the transmitter for full rate testing at 2,048Mbit/s
TX150 e-Manual D07-00-023 Rev A02
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