ZETRON 748, Technical Manual

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Operation
30 025-9368H
User number is simply an index into the User database (1 to 99 or 1 to 750). This is most commonly
used as the radio ID number for Phone-to-Mobile and Mobile-to-Mobile calls. This keeps the
overdial reasonably simple (two or three digits) for the person calling in.
ANI numbers are used by radios or mobiles in gaining access to the Model 748 from the radio
channel. These can be a single DTMF digit (short sign-on) or a DTMF sequence up to 10 digits in
length.
All interconnect calls, regardless of type, have three basic states: Call setup, Conversation mode,
Disconnect.
Call setup is the sequence of events required to establish a call. On Phone-to-Mobile calls, this
involves answering an incoming call, taking in a radio ID (user number or ANI), signaling the
requested radio or mobile, and the called radio or mobile answering. On mobile- originated calls, this
involves the radio or mobile sending its ANI, taking in a phone number or radio ID (User number or
ANI), dialing a phone number or signaling the requested radio or mobile, and the called party (phone
or radio) answering.
Conversation mode is the goal of interconnect, to allow the exchange of information between the
parties. Various conversation timers are started which will ensure shutdown if the radio or mobile
goes away. Various decoders that look for conditions to initiate a disconnect are also enabled.
Disconnect is the sequence of events required to shut down or terminate a call. This is the process
where the Model 748 returns to an idle state where it can process another call. Disconnect can be
initiated by a DTMF sequence sent by the radio or mobile (Disconnect ANI), or the phone party (“#”
or “#0”). Disconnect can be initiated by expiration of the call limit timer or mobile activity timer.
Disconnect can be initiated by detection of second dialtone, busy signal or loss of loop current.
TELCO ORIGINATED CALLS
Telco or telephone originated calls are those which are initiated by someone calling into the Model
748 from the telephone side (dialing the telephone number to which the Model 748 is connected).
The destination or called party is someone on the radio channel whose mobile is in the Model 748's
database. This can be a mobile, handheld transceiver, tone-only pager, tone and voice pager,
Talkback pager.
Call Setup (Telco)
To place a telco originated call, the caller must first dial the telephone number of the Model 748.
After the specified
Rings before answer have elapsed, it will answer the line and prompt the caller to
overdial a number. This will be either a prompt tone (925 Hz beep or Dial tone) or a “welcome”
voice prompt (prompt #1). The caller then overdials the number (user number or
Access ANI ) of the
user (radio) they wish to contact. The Model 748 then evaluates the number overdialed, if it finds an
enabled user (radio), the Model 748 responds with a “thank you” voice prompt (prompt #3), keys the
transmitter and sends any required selective calling sequence (paging tones), followed by ringing
tones to the mobile and the telephone caller. If the user (radio) is not enabled, error beeps or the
“invalid user” voice prompt (prompt #4) will be sent to the telephone caller, and the call is
disconnected. If the time restriction (Scheduled telco access) is not met for interconnect, the