Operation - Vocality V100 Technical Manual

However, with the TDM port as the aggregate, both PORT1 and PORT2 may be used as data ports with full
functionality, thereby effectively providing an extra channel.
Only transparent synchronous data channels may be operated in TDM mode. The format must be set to
"SYNC".

4.11.2 Operation

In the case of the TDM Framer, the serial interface behaves as an aggregate port, with a selectable
portion of the bandwidth able to be allocated to any tributaries configured in TDM mode. The remainder of
the bandwidth is assigned to all other channels and operates in the same way as a normal V100
aggregate.
The TDM Framer card (VI68713, required in RevC units only) may be fitted with a Vocality TDM Interface
card (VI68714) which carries DB15F connector and interface devices to provide the standard range of
transparent serial electrical standards. Unlike a standard port however, the TDM port can only be a DTE
and the RX clock MUST be supplied by the external DCE. The TX clock may be input externally or looped
from the RX clock; in both cases a Terminal Timing clock is always output to the connected DCE. The
DB15 pinout is the same as the standard V100 data ports.
The framer/deframer on the TDM Link card may be clocked at any frequency up to 512Kbps. This divides
the bandwidth into 32 timeslots, with up to a total of 28 assignable to TDM mode, while the remainder is
used for standard V100 packetised connections. A proprietary software protocol runs behind this which
time-division multiplexes data from any of the V100 tributary data ports on a byte-interleaved basis,
thereby providing optional TDM functionality to any ports configured with the format field set to "TDM".
In operation, the Time Slot Assigner (TSA) is used to separate a number of timeslots for TDM use and the
remainder for use by the normal V100 aggregate data stream, which is still available and may be used for
any other tributaries. The composite frame consists of 32 timeslots with the first four timeslots assigned to
synchronisation and V100 overhead, with the remaining 28 data timeslots allocated either to TDM data or
to V100-style packetised data:
S O O O T T T T T T T T V V V V V V V V V V V V V V V V V V V V
S= Synchronisation byte
O= Overhead
T= denotes TDM packetised sub-structure
V= denotes V100 packetised sub-structure
The allocation of slots defined by the configuration of the units. Sufficient timeslots are allocated to the
TDM channels according to the sum of all configured TDM channel rates, rounded up to the nearest
timeslot. At startup, all slots are allocated to the V100, allowing units to communicate and exchange
management data as normal. A simple protocol checks that both ends of an aggregate will use the same
V100 Versatile Multiplexer Technical Manual Version 2.2
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