Product Manual

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20-62 VHF & UHF TRANSMITTER
Product Manual
Sea Air and Land Communications Ltd, 10 Vanadium Place, Addington, Christchurch 8024, New Zealand June 2020
Configuring inputs:
• Messages for high or low states can be configured independently.
• Each input can be configured independently.
• The message format is described below (Sacoto message format).
• The number of transmission, the expected initial state, and other options can be
selected for each input and each state.
Input configuration examples:
The various input capabilities and settings can be demonstrated by way of these examples.
• The state of Input 1, both high and low states, are transmitted with every watchdog but
the input does not trigger messages when it changes. The watchdog is enabled on the
system tab. (see “Watchdog configuration” below) If the input message was enabled it
would also trigger messages when the input changes.
• When Input 2 changes, either to a high or low state, a “tone only” message is sent. There
is no text but the receiving pager can be programmed to produce different sounds for
“beep level 1” and “beep level 2”. The message is sent 3 times to ensure it is received. The
“message repeat time” is 5 seconds.
• When Input 3 is held low, the numeric message “3” is sent repeatedly (“while held”) at
1200 baud. This might be used for push button control of a remote relay. No message is
sent when the input returns to the high state.
• In this example Input 4 is normally held low by an external circuit (initial state = low). If it is
high at power-up (eg disconnected, or the circuit is broken) the message “I4HI” will be
sent. After start-up any change triggers either an “I4LO” or “I4HI” message. Setting
initial state = “Current” prevents transmission at power up.
In all cases the input must remain in the same state for 500ms (de-bounce time) before a
message is triggered.
POCSAG Rapid
POCSAG rapid allows even faster response to a push button input. POCSAG rapid uses a short
250ms preamble, and starts message transmission in the first frame, regardless of the CAP code.
This ensure the fastest transmission time. For even faster response keep messages short and
consider using numeric messages, reducing the de-bounce time and lead-in time, and using
1200 baud.
When POCASG rapid is used with the ”When held” option, messages are transmitted continuously
until the input is released. POCSAG rapid sends short messages in all eight frames of the POCSAG
data stream, rather than just the one of that corresponding to a single CAP code.
SALCOM relay receivers are able to provide quick response when configured to use POCSAG
rapid, giving faster response and more precise “on-time” control. POCSAG rapid should be used
with short numeric messages like the Salcom relay protocol.
Note: POCSAG rapid is not intended to work with pagers.