ZETRON 748, Technical Manual

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Operation
025-9368H 53
For a mobile on Site-1 to call Site-3, just key the radio and sends a long DTMF “3” and then unkey.
He can now hear the progression of the phone call through the PSTN. He will hear the phone
number being dialed, followed by the ringback tones from the Central office as the Model 748 at
Site-3 receives ringing voltage. When the Model 748 at Site-3 answers the line, it will send a
FASTNet answer sequence followed by the normal answer prompt. The Model 748 on Site-1 will
hear the FASTNet answer sequence and respond by over dialing a three digit user number. This is
the Page Forward User in the user programming. Following our example user group this would be
User 50. The Model 748 at Site-3 now keys the transmitter and issues a single ringout on the channel
(at Site-3). The mobile on Site-1 hears a single ringback followed by the go ahead prompt (short
low/high/low prompt) indicating that the audio path from Site-1 to Site-3 has been opened. The
mobile on Site-1 can now key up and do a voice hail to the other radios in his user group on Site-3.
Any radio in his user group on Site-3 can answer back by just keying their radio, just like any other
dispatch call.
Once the call is in process the timers and disconnect conditions that are running are the same as for
any interconnect call. mobile activity, call limit, detection of 2
nd
dialtone, loss of loop current or any
valid disconnect code. Either radio can initiate a shut down which will clear the other side down
using FASTNet commands again. Since the radios are DTMF equipped there would be no reason to
not have them clear the call down using a disconnect ANI (default is a long DTMF #).
Table 2. Interconnect Gateway Call Progress
Mobile in Site 1 Area 748 on Site 1 748 on Site 3 Mobile in Site 3
Area
Key radio and send long DTMF 3
and unkey Validate Short sign-on of
User #51.
Take phone line off hook
and execute autodial 21
Hear phone call being placed
through PSTN Audio path from Phone to
Mobile is opened Ringing voltage is detected
on Line 1 input
Hear ringing from CO as Site 3 is
called Answer ringing line, issue a
FASTNet answer sequence
Hear answer and overdial of
User # Receive FASTNet answer,
overdial Page Forward # Validate overdial of User
#50. Key TX and ring once
Hear ring followed by Go Ahead
prompt from Site 3 Issue Go Ahead prompt to
phone line and open audio Radio unsquelches
and ringing is heard
Key radio and voice hail Audio path is opened Hear audio from Site 1
Unkey radio and monitor Audio path is reversed Key radio and answer
back
Hear audio from Site 3 Audio path is opened
Audio path is reversed Unkey radio and
monitor
Key radio and send long DTMF #
to disconnect Validate disconnect
sequence from mobile
Send FASTNet hang-up to
Site 3 controller Receive FASTNet hang-up
Hear normal disconnect (5 fast
beeps) Call is compete Send telco side disconnect
tones to mobile Hear telco disconnect
(long dual tone)