3
Vega’s C-
6124
volume controls can be independently adjusted for a minimum level if desired. Up to six line cards can be installed on
each SBM.
2.3
End Bus Module (EBM)
The EBM is the last module of the console and houses both the Unselect speaker amplifier and the last six line card
slots.
2.4
Tone Line Module (TLM)
The TLM is a radio control card using either the standard tone control format compatible with Motorola and
Ericsson/GE or E&M relay closure. The line card may be hardware configured for either two-wire or four-wire
operation and may be factory modified to accommodate non-industry standard tone control formats if desired. The
TLM contains a tunable notch filter at the switched transmit audio input, so as not to talk-off the PTT tone when the
microphone is active. This audio is followed by a summing amplifier, where the PTT tone sequence and the DTMF
encoder are added. This combined audio is fed into the line driver amplifier, which drives a balanced interface to the
tone line at the appropriate levels. The receive audio is taken off the balanced tone line, amplified and processed,
then fed into the notch filter, and the DTMF decoder. The line activity detection circuit is branched off at the first
amplifier providing both status signals to the processor as well as a control signal for the line inactivity squelch. The
filtered audio is then switched into either the Selected or monitored audio busses. (Refer to 3.4 page 9 for
functionality).
2.5
Phone Line/Dial-up Modules (PLM/DLM)
The PLM is physically identical to the DLM. The only difference is a jumper position.
The telephone card has identical audio filtering and switching circuits as the TLM except for the interface to the
telephone line. A self-contained hybrid module houses the necessary circuitry to provide TX/RX audio isolation, off
hook enable and ring detect.
The DLM is the dial-up remote card intended to control a remote radio using Vega's Dial-up tone control format
(compatible with Vega Models C-550/RP-250 or RP-251).
The telephone interface is fully FCC and DOC approved. (Refer to 3.5 and 3.6 page 11 & 12 for functionality)
