TELEPHONE INTERFACE MODULE (TIM)

Table 14-2 E&M LEAD STATESM-Lead States for Type I through V

Type

IdleActive

 

 

 

I

Ground

-48V

 

 

 

II

Open

-48V

 

 

 

III

Ground

-48V

 

 

 

IV

Open

-48V

 

 

 

V

Open

Ground

 

 

 

E-Lead State for all Types

 

 

 

7 (Off), 8 (On)

Open

Ground

7 (On), 8 (Off)

Ground

Open

14.2.4 TYPE I AND V

A straight interconnect between the trunk circuit and signaling circuit. Two conductors are signaling and four are balanced audio (see Figure 14-4).

TRUNK

 

SIGNALING

CIRCUIT

RNT

 

CIRCUIT

 

 

 

E-LEAD

 

 

E-LEAD

 

 

M-LEAD

 

 

M-LEAD

 

 

TR1

TX AUDIO

RR1

T1

RX AUDIO

R1

Figure 14-4 TYPE I AND V

14.2.5 TYPE II AND III

A straight interconnect between the trunk circuit and signaling circuit. Two conductors are signaling, four are balanced audio and two are System Battery and System Ground (see Figure 14-5).

TRUNK

 

 

SIGNALING

CIRCUIT

RNT

 

 

CIRCUIT

 

 

 

 

E-LEAD

 

 

 

 

E-LEAD

 

 

 

M-LEAD

 

 

 

 

M-LEAD

 

 

 

SB

 

 

 

 

SB

 

 

 

 

SG

 

 

 

 

SG

 

 

 

 

TX AUDIO

 

 

 

 

TR1

 

 

 

 

 

 

 

 

RR1

 

 

 

 

 

 

 

 

 

 

T1

RX AUDIO

R1

Figure 14-5 TYPE II AND III

14.2.6 TYPE IV

This interface is a cross-connect between the trunk circuit and signaling circuit. Two conductors are signaling, four are balanced audio and two are System Battery and System Ground. This type of interface has the M-Lead and System Battery cross-connected (see Figure 14-6).

TRUNK

 

 

 

SIGNALING

CIRCUIT

RNT

 

 

CIRCUIT

 

 

 

 

E-LEAD

 

 

 

 

 

E-LEAD

 

 

 

 

M-LEAD

 

 

 

 

 

M-LEAD

 

 

 

 

SB

 

 

 

 

 

SB

 

 

 

 

 

SG

 

 

 

 

 

SG

 

 

 

 

 

TX AUDIO

 

 

 

 

 

TR1

 

 

 

 

 

 

 

 

 

 

RR1

 

 

 

 

 

 

 

 

 

 

 

 

T1

RX AUDIO

R1

Figure 14-6 TYPE IV

14.2.7 TYPE II TRUNK-TO-TRUNK

Some applications may require an interface to another trunk circuit (e.g. PBX). This interface is a cross-connect between trunk circuits. Two conductors are signaling, four are balanced audio and two are System Battery (SB) and System Ground (SG). The System Battery and System Ground are cross- connected with the E-Lead and M-Lead (see 14- 7Figure 14-6).

14-6