Network Connection - JPS QMT-1B Installation And Operation Manual

QMT-1B Operations Manual
through a 22K ohm resistor. The logic threshold is 2.5V DC nominal, and the input is protected
from momentary surges up to +100 V DC.
2.7.3.4 PTT Output
The PTT output from the QMT-1B is an E&M relay type that grounds the PTT output when
active. The PTT output can also be configured to be an open drain type which can sink up to
100 mA of current and can withstand open-circuit voltages up to +60V DC. In order to avoid
conflicts with internal pull-up resistors on the PTT lines of some radio equipment, there is no
internal pull-up resistor on the NXU-2B PTT output.
The QMT-1B is configured for E&M relay PTT when it leaves the factory.
2.7.3.5 E&M Return Selection
When the PTT source is set to use the internal relay, the user may select either an internal
GROUND as the return or an external pin on the Audio/Control jack as the return. This is for
E&M applications where some PTT reference other than ground may be desired. To select the
internal GROUND reference place J13 (E&M Return) in the Ground position. When an
alternative reference is desired place both J13 and J15 in the right position. The desired E&M
return voltage may then be applied to pin 4 of the Audio/Control jack.

2.7.4 Network Connection

The QMT-1B is connected to the Ethernet network via a standard Ethernet Patch Cable (non-
crossover, plugged into the rear panel RJ-45 connector.
2.7.5 RS-232
This connector currently has no field use with the QMT-1B application.
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