Unit installation

…always there

The STU provides two different modes of local line monitoring, which can be

selected when the NVM is programmed. The ARC must be notified if local line

monitoring is to be enabled, and if so, which mode is required.

For STUs connected to normal phone lines, ‘PSTN mode’ should be used. This

mode monitors the DC line voltage and triggers the Line Fault output within 100

seconds of a line break.

For STUs connected to private wires (RedDIRECT), ‘Private Wire mode’ should be

used. This mode causes regular ‘chirps’ on the line and triggers the Line Fault

output within 3 minutes of a line break.

In both PSTN and Private Wire modes, the Line Fault output will be triggered

within 40 seconds if the STU has an alarm to transmit but cannot communicate

with the redcare system.

Telephone Line Selection (LK1)

The STU is supplied ready to connect to the Public Switched Telephone Network

(LK1 is not fitted). If the STU is to be connected to a Private Wire (RedDIRECT) a

suitable link must be fitted in the position marked LK1. An NVM chip must be

configured for PW use and fitted in accordance with the procedure on page 17.

If you have any doubts about the type of telephone line to which the STU is being

connected, contact BT redcare for advice.

INSTALLING THE NVM

The NVM (Non-Volatile Memory) chip is a device used by the STU to store

configurable parameters. This memory is retained even when the power is

completely removed.

There is a socket provided (at IC2) for the fitting of a pre-programmed NVM.

Suitable NVMs for use with the STU are National Semiconductor NM93C46N or

Microchip Technology 93C46/P.

The NVM can be supplied pre-programmed by the ARC or the NVM can be

manually programmed using a Scantronic 7200 NVM programmer (version 1.2 or

1.3 software) or a Scantronic 7300 NVM programmer (version 1.3 software).

Once fitted, the NVM can be re-programmed after careful removal using an IC

extractor. If the unit has already been commissioned, see the note on page 4.

The STU and alarm system must be totally powered down (switch off mains

power and disconnect the battery) before fitting or removing the NVM.

Note the orientation of the device shown below and make sure it is fitted the

correct way around.