Sailor SC4150, Installation Manual

15

Installation

IRIDIUM

0225

2.8

PABX/PSTN Interface

This interface handles and converts 2-wire audio and control signals from/to the PABX into audio and control signals
from/to the LBT. The interface is placed on the control unit BUS, allowing the PABX to act as control unit. The interface
handles the following tasks:

·

generates DC current to the PABX in both idle and active mode

·

generates ringing voltage

·

detects call requests from the PABX

·

detects DTMF tones from the PABX

·

converts audio TX/RX from the Iridium system to a 2-line balanced signal

This means that an ordinary two-wire system telephone can be connected to the onboard PABX unit/PSTN socket -
and the call can then be initiated from this telephone, e.g. from the captain’s cabin or the cargo control room. The built-
in SMPS of 10-32 V DC generates the necessary current to support the PSTN telephone of the system.

Specification of the Iridium system PSTN connection:

RJ11 connection:
1. nc
2. TIP
3. RING
4. nc

Line Voltage:

48V DC

Line current (source):

24 mA

Line impedance:

270 

W

 + 750 

W

 // 150 nF (this impedance also covers 600 

W

)

Ringing voltage:

60VRMS, 90 Vpp (square wave)

Ringing sequence:

0,6 sec On, 4 sec Off.

Ringing frequency:

30 Hz

Ringing drive capability: 1400 

W

 @ 30 Hz (= 5 normal ring units)

2.9

Data Interface

The Iridium terminal includes a 9 pol Sub-D connection. The connection is a RS232 interface.
For using this interface, please contact your Iridium Service Provider, that will supply you with Iridium Data Interface
software