System information

Again, Asterisk defaults to the North American caller ID format (no entries in /etc/
asterisk/chan_dahdi.conf describe this, it’s just the default), and in order to change it
we will need to make some entries that describe the technical details of the caller ID
system. In the case of the UK, the delivery of caller ID information is signaled by a
polarity reversal on the telephone line (in other words, the A and B legs of the pair of
telephone wires are temporarily switched over), and the actual caller ID information is
delivered in a format known as V.23 (frequency shift keying, or FSK). So, the entries in
chan_dahdi.conf to receive UK-style caller ID on any FXO interfaces will look like this:
cidstart=polarity ; the delivery of caller ID will be
; signaled by a polarity reversal
cidsignalling=v23 ; the delivery of the called ID information
; will be in V23 format
Of course, you may also need to send caller ID using the same local signaling informa-
tion to any analog phones that are connected to FXS interfaces, and one more entry
may be needed as in some locations the caller ID information is sent after a specified
number of rings. If this is the case, you can use this entry:
sendcalleridafter=2
Before you can make these entries, you will need to establish the details of your local
caller ID system (someone from your local telco or Google could be your friend here,
but there is also some good information in the sample /etc/asterisk/chan_dahdi.conf
file).
Language and/or Accent of Prompts
As you may know, the prompts (or recordings) that Asterisk will use are stored in /var/
lib/asterisk/sounds/. In older versions of Asterisk all the sounds were in this actual di-
rectory, but these days you will find a number of subdirectories that allow the use of
different languages or accents. The names of these subdirectories are arbitrary; you can
call them whatever you want.
Note that the filenames in these directories must be what Asterisk is expecting—for
example, in /var/lib/asterisk/sound/en/ the file hello.gsm would contain the word
“Hello” (spoken by the lovely Allison), whereas hello.gsm in /var/lib/asterisk/sounds/
es/ (for Spanish in this case) would contain the word “Hola” (spoken by the Spanish
equivalent of the lovely Allison
†
).
† Who is, in fact, the same Allison who does the English prompts; June Wallack does the French prompts. The
male Australian-accented prompts are done by Cameron Twomey. All voiceover talent are available to record
additional prompts as well. See http://www.digium.com/en/products/ivr/ for more information.
190 | Chapter 9: Internationalization