ZETRON 748, Technical Manual

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Operation
025-9368H 33
MOBILE ORIGINATED CALLS
Mobile originated calls are those which are initiated by a radio or mobile on the receive frequency or
channel to which the Model 748 is connected. To initiate a call from the radio channel, the mobile
must be capable of encoding DTMF. The Model 748 identifies the originating mobile by using it's
Access ANI (Automatic Number Identification). In the Model 748, this is a DTMF sequence, 1 to 10
digits in length, using any of the 16 DTMF tone pairs. There is an Access ANI for each user (radio)
in the database.
Users (radios) may be allowed to make outgoing telephone calls, Mobile-to-Mobile calls, or mobile-
repeat (dispatch) calls. If a mobile is only allowed to use one of these privileges, the user simply
keys the radio and enters his
Access ANI to gain access to the Model 748. If the mobile is allowed
access to more than one of these privileges, a steering digit must be appended to the end of the ANI.
The steering digits are as follows:
5 = access code for mobile repeat (dispatch) mode
7 = mobile to mobile, Talkback, pager or Tone and Voice pager
* or 9 = mobile to telephone
Call Setup (Mobile)
To place a mobile originated call, the radio or mobile must first identify itself to the Model 748. This
is done by transmitting its
Access ANI along with any sub-audible tone/code required. The Model
748 validates an ANI in 3 ways; 1) finds a match in the user database, 2) verifies the decoded
tone/code matches the ANI found in the user database, 3) verifies that the complete ANI was
captured within the minimum time requirement, typically one digit per second (five digits per second
if
Fast ANI access is enabled). If the Model 748 finds a valid ANI, but it is not enabled, the Model
748 ignores the ANI. If the time restriction (Scheduled telco access) is not met for interconnect, the
“interconnect not available at this time” voice prompt (prompt #9) is sent to the mobile, and the call
request is terminated.
For users (radios) that are allowed access to only a single privilege, no steering digit is required.
For users (radios) that are allowed access to multiple privileges, the Model 748 will keyup and send
the
Steering digit prompt (dialtone or 925 Hz beep), indicating “Please enter your steering digit
now”. The Model 748 allows up to five seconds for the mobile to enter a steering digit.
The Model 748 verifies that the steering digit received is a valid request for the originating user
(radio). If the steering digit is not valid, the Model 748 will keyup and send an error tone to the
mobile and terminate the call request.
Note that the Model 748 is capable of buffering the digits from the radio. This means a radio could
send a 10 digit ANI + steering digit + 10 digit phone number in a single DTMF burst. The Model
748 will process the string just as if the radio unkeys in between the ANI and phone number.