Telex MCE325 Electrical Installation, AC Power and Fuse, Intercom Lines J8, J9, and J10, General

Electrical Installation

AC Power and Fuse

The Model MCE325 is pre-wired for either 115 or 230 VAC operation, and the appropriate fuse is already installed. The MCE325 uses a 0.5A Slo-Blo fuse for 115 volt operation, or a 0.25A Slo- Blo fuse for 230 volt operation. (A fused external DC source may be used instead of AC power if desired. (See “External DC Power Source”.)

Intercom Lines J8, J9, and J10

General

Intercom line connectors J8 and J9 are parallel-wired for loop-through connection to other intercom stations. These connectors are used for connection of two-wire lines to channels one and two (full-duplex operation), or for connection of four-wire channel A output (channel A input is connected at the auxiliary connector).

Intercom line connector J10 is used for connection of two-wire lines to channels three and four (full-duplex operation), or for connection of four-wire channel B output (channel B input is connected at the auxiliary connector).

Connector Pin-outs

Table 2.4 Connectors J8 and J9.

PIN # FUNCTION

1Common (low side of line)

2Two-wire CH 1 or four-wire CH A high output

3Two-wire CH 2 or four-wire CH A low output

Table 2.5 Connection J10

PIN # FUNCTION

1Common (low side of line)

2Two-wire CH 3 or four-wire CH B high output

3Two-wire CH 4 or four-wire CH B low output

Four-wire Output Termination

Figure 2.4 4-wire output terminations.

When four-wire outputs are used, termination resistors must be installed for proper operation. The output amplifiers are current sources, and the output level is determined by the terminating

2-8C S I - 2 0 0 U s e r I n s t r u c t i o n s