Telex 1505 Securing the Connections, Interface connector Numbering, Operation Description

Page 6

4.4 Securing the Connections

After all power and line connections are made, the wires should be neatly bundled and secured in place to prevent accidental breakage when in service. Use one or more of the cable guides supplied with the card rack, or tie in place with appropriate wire ties.

4.5 Interface connector Numbering

The Tellabs (or equivalent) card cage interface connector pins may have a different numbering scheme than the 1505. Table 4 depicts the card edge pin numbers as shown in the schematic, which is also the same as one type of connec- tor, followed by two alternate numbering schemes as used on other connectors. Dili- gently review the actual connections being used, to Table 4, to ensure proper connections are made for optimum performance. Record the external connections made during installation in the blanks rows in Table 4’s “User Connec- tion” column (make copies of Table 4 and keep records for each 1505).

5.Operation

5.1 Description

This 1505 module has up to four, receive bal- anced 600 Ω line inputs or high impedance un- balanced inputs, along with a Mic/Handset in-

put, that is user configurable by dip switch set- ting, to drive from one to four 600 Ω balanced transmit line outputs, or an 8 Ω remote speaker. The module is also capable of summing up to four receive channel inputs and/or a Mic/Hand- set input, into one or more transmit line outputs or the speaker output.

A compressor/limiter circuit is available by jumper selection for each receive circuit, to limit the input level to a predetermined setting, which assists in maintaining proper system lev- els. This module also contains a summed input circuit, and a summed output circuit, to allow it to be used in a matrix, i.e. three modules can be configured to allow a single input to drive twelve outputs, or conversely twelve inputs can be summed to one output.

Active switch input circuits allow for muting individual receive input channels, or the speaker. A PTT input activates the microphone circuit.

5.2 Operating Capabilities

The 1505 accepts up to four balanced or unbal- anced inputs, switch selectable by the user, to four balanced line driver outputs. These inputs are also externally mutable by switched low in- puts at the rear panel connection. In addition, the module will accept a microphone or hand- set input through the front panel jack or the rear panel connector.

The transmit amplifier is a 600-ohm balanced line output. The module has four balanced line outputs. Each amplifier output is adjustable with a range of -15 to 10 dBm.

The module has a speaker amplifier output that may drive an eight ohm external speaker with an output level of 1 watt. The level is adjust- able.

Any line or microphone input may be switched (through a module dip switch) to any line out- put or the speaker output. Three 1505s can be connected so one line input may drive up to twelve 600-ohm line outputs. Each input is mu- table and the control is a switched low on the rear panel connector. A PTT from the micro- phone or handset will gate on the microphone amplifier and is also jumper selectable to mute the speaker to inhibit crosstalk.

5.3 Controls and Indicators

Front panel LEDs light when the corresponding receive channel or speaker is muted and when the microphone or handset PTT switch is acti- vated.

5

Image 6
Contents Audio Line Driver Table of Contents Optional Features includeInspection Access for Installation/Servicing PowerMounting Signal Connections and Card Edge Con- nector Pin Assignment Function Jumper Status OutJumper Options Receive Line Input Impedance Switch SettingsMicrophone Jumpers Parallel Transmit Line Impedance MatchingSecuring the Connections Interface connector NumberingControls and Indicators Operation DescriptionCard Edge Connector Pin Assignments Solder Side Component SideCompression Limiter Circuit Theory of Operation GeneralReceive Amplifier Transmit Line AmplifierPage Page Page Warranty Limited IndicatorsPower Supply Microphone InputSpecifications Parts List Part No. Description Ckt Sym Conn Jumper Plug JP1 JP2 JP3 JP4 JP5 JP6 JP7 JP8 JP9 East Cornhusker Highway, Lincoln, Nebraska