Nortel Networks RTU-292 Audio Level Setup and Adjustments, 5 RS-232 Connection, 10.1.1

RTU-292 Operations Manual

2.9.5RS-232 CONNECTION

Use P2 on the rear panel to connect to the RTU-292 RS-232 interface. RS-232 control is fully explained in section 5.

Table 2-19P2 – RS-232 Connector (DB-9 Male)

Pin Function

1No Connection

2RS-232 RX Input

3RS-232 TX Output

4Reserved- Do not connect

5Ground

6Reserved- Do not connect

7No Connection

8No Connection

9No Connection

2.10AUDIO LEVEL SETUP AND ADJUSTMENTS

For proper operation of the RTU-292, the radio transmit and receive levels must be properly set. The radio receiver level into the RTU-292 is of particular importance, because excessive level here can cause telephone line overloading, distortion, VOX falsing and poor hybrid operation. It is also important that the output level to the transmitter be set so that excessive compression does not occur in transmitters with a compressor.

2.10.1 SETTING THE TRANSMIT LEVEL

There are two ways (detailed below) to set the transmit level: First apply TX audio by one of

two methods: (A) Use a 1 kHz test tone supplied by the RTU-292 when in the Transmit Level Set-Up Mode, or (B) simply speak into the telephone line to supply typical audio to the RTU-

292.Next, rotate the internal TX Level Adjust R133 so that the transmitter is just fully modulated. Either method will set the correct transmit level in the majority of cases. The radio may also have a TX audio level setting procedure in its installation manual. If so, use the radio’s procedure in conjunction with the directions below.

2.10.1.1

(A)Set-Up Mode. Enter the Set-Up Mode by turning off the unit, setting dipswitch SW2-7 to ON. Turn unit power back on. In this mode, the RTU-292 DSP module generates a test tone at the same amplitude as voice peaks received on a telephone line, and applies this tone to the RTU-292 transmitter output. While in the Set-Up Mode, key the transmitter by pushing the KEY pushbutton or by other means. If using (B) Telephone Line Method; simply press the TEL-LINE-RADIO button and speak into the phone.

2-15 JPS Communications, Inc.