Specifications

Figure 11 Telephone RJxx Jacks

A third common telephone jack is RJ31X used with alarm circuits. This is an 8-position connector. The

jack is placed in series with one phone line close to the NID so extension phones are downstream of the

jack. When the alarm system is plugged in the jack opens the phone circuit. This places the alarm in series

with the phones. When the alarm is activated it disconnects the phones so it is able to dial out even if the

line was in use.

5.6 Type 66 Terminals

The first type of insulation displacement terminal developed by the

telecom industry was the Type 66 block. These continue to be

extensively used. Types 66 blocks accept large number of accessories.

For telephone wiring one advantage of the 66 family is that it accepts

larger gauge wire then the 110 system.

Type 66 blocks are typically clipped to a standoff bracket that is

screwed to the wall. The bracket allows cables to be run underneath

the blocks.

Building wiring is terminated on one set of terminal blocks and

equipment on a different set. To interconnect equipment to the

specific jack single pair cross connect wire is used. This allows a great

deal of flexibility in adding and changing equipment over time.

5.6.1 Type 66 Accessories

The Type 66 family includes a number of accessories and options.

Standoff: Type 66 block clips to standoff. This allows building wire to be routed through the

standoff under the block.

Bridging clips: Blocks normally consist of 25 terminal pairs vertically and 4 terminals across. A

common variant is the split block. This divides each horizontal row in half doubling the number of

circuits. A bridging clip connects all four horizontal terminals. Bridging clips make troubling

shooting easier since simply removing the clip opens the circuit.

Test clips: come in several flavors that facilitate connecting test equipment to the block

Cover: Protects the 66 block terminations from foreign objects.

Mushrooms: Cross-connect wire can become unsightly if not managed properly. Mushrooms

screw to the wall to create wire routing channels.

Line use Indicator: LED indicator that show when a phone line is in use.

Figure 12 Type 66 terminal

block