Specifications

ST900 Family General Handbook
667/HB/32900/000 Issue 11 Page 239 of 265
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37.1 General Description
The Integral TC12 OTU is a double extended Euro sized card which connects to the
ST900 Main Processor via the Extended System Bus. For more information on the
Integral TC12 OTU, refer to the TC12 General Handbook 666/HB/43100/000.
Handset access is via the handset socket on the Main Processor board, with the
main processor automatically redirecting OTU handset commands to the OTU Card
without the user needing to actively ‘switch’ between the main processor and OTU.
The Integral TC12 OTU provides an Outstation Transmission Unit for use in a TC12
UTC Data Transmission System. Also see section 15 for more information on the
UTC (Urban Traffic Control) facility.
Telephone Line Interface: There is a BT style jack provided to allow 2 or 4 wire
leased line connection to the TC12 UTC Instation.
A Jack socket is provided to allow connection of a TC12 Instation Test Set. This
permits monitoring of line levels and communication data during installation and
maintenance etc.
The card includes its own:
 Firmware PROM
 RAM (battery supported)
 Shared RAM (‘shared’ with the ST900 Main Processor)
 Serial Interface (USART) with integral Modem and Line Interface
 Watchdog Monitor Facility
 Status LED Indicators
37.2 Detector Inputs
Where the Integral OTU is required to monitor vehicle detectors (count or SCOOT
loops for example) in order to provide reply bit information to the UTC System, these
detectors should be connected to the controller I/O. The Integral OTU Card does not
have its own input / output circuits and instead the OTU firmware reads the states of
the controller I/O.
NOTE
A limitation of the OTU firmware means that it can only read the states of
the first 12 Controller I/O Ports, detector numbers 0 to 95. Thus, any
detectors that the OTU needs to monitor must be fitted to those ports.
37.3 Upload / Download and Remote Handset
In addition to providing UTC control and reply, the integral OTU also allows
controller data to be uploaded to and download from the UTC Instation. For
example, the controller’s fault logs can be uploaded and viewed at the Instation,
while configuration data that can be altered via the handset, such as the CLF plans