MX800 Transceiver
Technical Manual
1.2 2Wire or 4Wire Selection, Balanced VF
Description
Option T19 and T26 both provide the user to be able to select between 2 wire or 4 wire systems,
they also both have balanced and isolated VF I/O as well as isolated E (PTT) and M (Mute) leads.
The T19 has dual E&M leads, this provide a Qualified and Non-qualified M leads as well as E
leads with subtones and with out subtones. The second E&M connection points are found on CN3
DB25 connector.
The E lead is opto isolated and may be asserted by applying a DC voltage between 5V and 48V
with any polarity between CN9 Pins 7&8 (JMP4 & JMP5 removed).
Provision is also made to internally source or Earth (JMP4 and JMP5) so that the activation can
be done Via CN9 Pin8 (+12V DC) or (GND), in which case the E lead is asserted by grounding
or pulled up to 5V (depend on JMP4 & JMP5 settings) on CN9 Pin8
The M lead is relay isolated and the common and normally open contacts are brought out via
CN9 Pins 5&6. The relay contacts are rated at 500mA.
Note
In REV C PCB for 2 wire mode, to have the correct matching for 600R please fit a 560R resistor is in parallel to R77(above IC4) and
across R130 & R129 (Right hand side of PCB above RV4)
1.3 T19 / T26 Secondary E&M leads
The MX800 T19 option board has a secondary E & M lead designated E2 and M2 respectively.
Unlike the primary E & M leads that appear on both the RJ45 and DB25 connector, the E2 and
M2 leads are only present on the DB25. The assertion of the E2-lead will cause the transmitter to
transmit without a subtone, even if one has been programmed for the channel.
The M2-lead is used to indicate the state of the RF (unqualified) mute. The M2-lead can be
programmed to close the relay contacts when the mute opens or operate in reverse. The secondary
E & M leads are enabled in the hardware configuration menu (
C
onfiguration Menu ->
H
ardware
Configuration).
The E2 and M2 Leds on front panel show the activity on these lines only if the “Glide Tone” or
“Stepped Glide Tone” modes are not selected.
Front Panel
Led Position
Led
Colour
Standard Function
Glide tone Led Function.
(RF Signal Decision Points)
1
Amber
E1 Lead, indicates status of E1 input.
Level 0 signal (> 0uV)
2
Green
E2 Lead, indicates status of E2 input.
Level 1 signal (> 0.6uV).
3
Green
N/A
Level 2 signal (> 1.0uV)
4
Green
N/A
Level 3 signal (> 2.0uV)
5
Green
M1 Lead, indicates status of M1 input.
Level 4 signal (> 5.0uV)
6
Red
M2 Lead, indicates status of M2 input.
Level 5 signal. User defined
Table 1-1 T19/T26 Font Panel Leds
12
© SPECTRA ENGINEERING 2010 Revision 1.0.4