Sea Air and Land Communications 1178 User Manual

11-78-0000 SYNTHESIZED NRZ DATA TRANSMITTER PRODUCT INFO

Issue 11787TA

11-78-0000 SYNTHESIZED NRZ DATA TRANSMITTER PRODUCT INFO

Issue 11787TA

Sea Air and Land Communications Ltd

Page 2

Sea Air and Land Communications Ltd

Page 3

therefore inherently Year 2000 compliant.

External indicators consist of a power indicator GREEN  LED, normally

WARRANTY   

The RED LED will indicate when the unit is transmitting. A flashing

Our Products are warranted for a period of 12 months from date of
purchase against faulty materials and workmanship.  Should any fault
occur the unit should be returned to the vendor, freight pre-paid. 
Please include a description of the fault to assist with prompt return.
Any unauthorized alterations or repairs will invalidate the warranty.

The 1178 will power on, and will remain in the standby mode until the

DISCLAIMER   

All information provided in this document is carefully prepared and

The transmitter will be placed in transmit mode by the PTT (Press To

offered in good faith as a guide in the installation, use and servicing of

Talk) input being taken low. It will then turn the carrier on at the preset

our products. Installers must ensure that the final installation operates

power level, as defined in the configuration. The carrier frequency will

satisfactorily within the relevant regulatory requirements. We accept no

follow the Data1 input, a high input giving high frequency shift.

responsibility for incorrect installation. 

Data2 input acts as a channel busy inhibit, when taken low it will stop

We reserve the right to change products, specifications, and installation
data at any time, without notice.

An input can be initiated with a transition to LOW (connection to GND

MECHANICAL DESCRIPTION  

>+3.5v).

The 1178 is enclosed in a solid aluminium box. All electrical
connections are made via the D15 socket S2 or P2, the two pin power
connector. 

If the 1178 does not perform as required, the following points may lead

The unit can be mounted on a wall with 4 screws. It is advisable to

to solving the problem.

mount it away from sources of heat, damp or vibration.

INSTALLATION   
The configuration of the unit should be completed before installation.

The power supply should be connected as illustrated, at a voltage
shown in the specification. The supply input is protected against
reversed connection. The aerial connection is via the BNC connector,
and should present a nominal load of 50 O, with a VSWR of better than
1.8:1. It is recommended to site the aerial a few metres away from the
1178 to avoid any possibility of RF feedback causing problems with 
the transmitter operation. An outside aerial is preferable, as it will
provide better radio coverage.

ON with very brief flashes to indicate healthy micro-controller operation.

RED LED indicates the unit cannot transmit as either the synthesiser is
out of lock or the channel busy input is active.

PTT input is activated.

the transmitter coming on air.

or connection to <+3.5v) or HIGH (input floating or connection to

No illumination of Green LED

Bad power supply connection

PTT input activated but no

Transmit inhibit /Channel busy input

transmission, red LED flashes

active.

Unit transmits but nothing received

Poor aerial. Wrong frequency, Power too
low. Unit too hot. Too much vibration

No RS232 serial communication

Comport connections, baud-rate (9600)
no parity, eight data bits, one stop bit

Red LED flashes rapidly. No

Frequency out of range, Channel busy

synthesizer lock.

active.

Unit starts, but does not complete

Poor supply volts, RF interference.

transmission

Does not remain in transmit mode

“Max On Air Time” too short