Figure 1-6. Transmit Output Level Switch

TM 11-7025-234-23

(1) Shutdown Feature. The jumpers which cause the power supply to shut down

upon removal of boards A3 or A4 are on EF and GH (fig. 1-7). These jumpers are

placed on AB and CD to override the shut down feature for troubleshooting.

However, they should be returned to EF and GH when the modem assembly is placed

back into normal operation.

(2) Transmit Output Level Switch. The transmitter output signal level is

controlled by a ten position screwdriver-adjustable switch located near board A7

(fig. 1-6). Position O terminates the transmit line in 600 ohms.

WHITE DOT

INDICATES

POSITION

OF SWITCH

SCREWDRIVER

ADJUSTABLE

1O-POSITION

SELECTOR SWITCH

Figure 1-6.

Transmit Output Level Switch

(3) Ground Jumper. A ground jumper (fig. 1-7) is provided to connect

protective ground

pin 1 to signal ground pin 7 J1 thru J4) to signal ground (AB

pin 7 J1). This ground jumper is factory set as shown in figure 1-7 (AC to DC

ground or Signal to Chassis Ground). The other terminal is used only when a ground

fault is suspected or when ground has an unsatisfactory noise level.

1-11