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ITIS Phrase Tables, Draft [issued: 04-11-09]
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218 -
This is a draft document of the SAE ATIS committee, subject to change.
It should be noted that the textual expression of the ITIS phrases is always in lower case. This is
due to restrictions of the combined ASN and XML language used and does not apply to how the
term might be displayed to an end user. There is no distinguishing emphasis placed on
capitalization in the use of ITIS phrases. It is not uncommon for device developers to reformat the
final string before presentation to an end user to further refine this.
When free text needs to be expressed, the form used is to show it bracketed with the text keyword,
a semicolon, then the text in question. Note that using the text this way does allow for
capitalization in expressions. As an example, the text for the phrase “This is text” would be
shown as <text: “This is text”>.
Examples of well formed use show the example in three columns. The first is the raw concept to
be sent, the 2nd shows the specific ITIS phrase element in brackets, the final column has the same
elements in their encoded value.
When the resulting expression is rendered for use over the wire in XML, the ITIS and text
elements are rendered as per the defined schema for ITIS or the using standard. That is,
expressions appear in sequences such that shown below. The expression “Exit Glendora Ave,
ahead, 2 miles” would be encoded as:
<itis>exit</itis>
<text>Glendora Ave</text>
<itis>ahead</itis>
<itis>n2</itis>
<itis>miles</itis>
93 characters w/overhead
Note that XML is typically rendered into its textual equivalent form; however, the union of the
numerical values allows the below expression to considered equivalent (or any combination of
mixed use as well). Typically, this rendering is shorter than the full text format above.
<itis>11794</itis>
<text>Glendora Ave</text>
<itis>13312</itis>
<itis>12546</itis>
<itis>8712</itis>
93 characters w/overhead
When this same expression is rendered into ASN (particularly using BER encoding), then the ITIS
codes are sent as 2-byte long values with whatever encoding tagging is defined by the standard. In
some message sets, free text is not allowed and the above message would be reduced to four 2-
byte values enclosed in a single tag (the value of which will be context defined) and a length value
as in:
<tag>
<length>
<value>
<0x80>
<0x08>
<11794>
<13312>
<12546>
<8712>
10 bytes w/overhead
If the ASN rendering allows the free text and handles the ITIS codes individually (the literal
translation of the text-and-itis data frame defined in this standard) than the resulting tagging would
be similar to:
<tag>
<length>
<value>
<0x80>
<0x02>
<11794>
<0x81>
<0x12>
<Glendora Ave>
<0x80>
<0x02>
<13312>
<0x80>
<0x02>
<12546>
<0x80>
<0x02>
<8712>
22 bytes w/overhead