EMS Technologies Canada Ltd. HSD-400 Manuale Utente

Each dialing sequence component serves a different routing function:

•

Use service-specific dial code prefixes when sending a fax or using analog modems, 
or for overriding system defaults to force the system to request a specific service type. 
Figure 2-2 uses the dial code prefix for 3.1 KHz audio service type (*82*). See “Dial 
Code Prefixes” on page 2-16 and Table 2-7 for more information about dial code 
prefixes.

•

Use the international code of the ground location where the call is originating when 
calling the aircraft during ground-to-air calls. The international access code for all 
airborne equipment is 00. 

•

Use the Public Switch Telephone Network (PSTN) number assigned to the country of 
your call destination. (Example: “1” is the Country Code for North America.)

•

Use the PSTN routing number assigned to the area (and if applicable, city) of your 
call destination. 

The telephone, fax, or network number of your call destination.

•

Press # (or enter # at the end of the phone number field on data devices) to signal 
the system to send the call. Certain devices using the HSD-400 terminal may not have 
the functionality to insert the # symbol at the end of the dialing sequence. For those 
devices, additional Dial Code Prefixes are required to override the send command 
requirement. Refer to Table 2-8 for more information.

(1) Dial Code Prefixes

Although the system automatically selects the appropriate service types on outgoing 
calls for ISDN devices, a Dial Code Prefix is required to send a fax, identify an 
analogue modem, or force the system to override the system defaults to select a 
specific service type (see Table 2-7). 

The system requires the Dial Code Prefix *82* for sending fax or when using analogue 
modems; it forces the system to request the required 3.1 kHz audio service from the 
Inmarsat Satellite Communications Network. If required, use the Dial Code Prefixes 
to override the system defaults for selecting specific service types. Dial Code Prefixes 
for all service types require an asterisk ( * ) before and after the code number.

Other Dial Code Prefixes provide system overrides required if you are using devices 
that cannot add a # symbol to the dialing string or devices that are slow dialing. Table 
2-7 provides a description of the additional Dial Code Prefixes used for system 
overrides for Swift64 and SBB services. Table 2-5 on page 2–10 provides a list of the 
LES and their associated codes available. 

For SBB, prefix *81* can be used for AMBE+2 instead of 64 kpbs speech. Prefix *82* 
is required for fax, modem, STU-III, and STE services. If no prefix is used, the SBB 
service defaults to AMBE+2.