User Manual

14221-1400-2000
51
The V-TAC supports three Extended Coverage modes: Extended Coverage for individual users (XCOV),
Extended Coverage for a talk group (XCOV-TG), Profile Extended Coverage (XCOV-PROF). Typically,
Extended Coverage is used after the vehicle’s operator has exited the vehicle with a portable radio unit
and the portable unit requires this bridging functionality to access the OpenSky radio network.
The V-TAC takes advantage of OpenSky’s TDMA capability to eliminate interference between its local
and network radio links when operating in an Extended Coverage mode, an undesirable characteristic of
many traditional vehicular repeater systems. Because the V-TAC employs this technology, interference
on the network and local radio links is minimized.
A V-TAC in Extended Coverage mode sends its alias to clients. The alias is displayed in the second line
of the dwell menu of the client, (“VA <alias>”). The client must be connected to a V-TAC running
version OTP14.4 or for the V-TAC to provide the alias to the client. If the client is connected to a V-TAC
running version OTP14.3.1 or earlier, the client displays “VA None.”
8.33.2 Change Between Extended Coverage Modes
By default, the specific Extended Coverage mode utilized is determined by commands sent to the V-TAC
and portable radios from the system administrator or radio installation personnel. These commands
determine which Extended Coverage mode the V-TAC and radios normally use and determine the access
method employed by a portable radio to connect to the V-TAC. After these commands are sent to the
V-TAC and portable radios, each must be rebooted (powered off and then back on) before the change
takes effect.
See the following sections for instructions on how to override this command manually. Note that the
override is only successful if the V-TAC operating mode matches the manually selected portable V-TAC
mode.
8.33.3 Radio Limitations Using Extended Coverage Modes
Connecting a portable radio to a V-TAC introduces minor functional limitations. See the following
sections for a listing.
8.33.3.1 Limitations Using Both XCOV and XCOV-TG
Portable radios connected to the V-TAC using either of the Extended Coverage Modes, XCOV or
XCOV-TG, will not channel-scan unless they lose radio frequency contact with the V-TAC. If manually
enabled, radios will not scan network channels.
8.33.3.2 Limitations Using XCOV-TG
The following portable radio keypad functions are disabled when the radio is connected to the V-TAC
using the XCOV-TG mode: log-off, manual log-in, alerts, selective calls, PSTN calls, and speed dial
calls.
The following portable radio menus are disabled when the radio is connected to the V-TAC using the
XCOV-TG mode: alert destination, alert message, alert received, priority talk group, and scan mode. In
addition, the user cannot change talk group or profile.
8.33.4 Use XCOV Mode
The Extended Coverage for individual users (XCOV) mode allows up to eight (8) client radios to connect
to the V-TAC. The radios have full radio functionality including selective calling and mobile data.
With the Extended Coverage for individual users’ (XCOV) mode, V-TAC configuration defines which
portable radios are permitted V-TAC access. The radio will automatically connect to a V-TAC if it