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Q5: Why do we use 110 punchdown block?
A5: Punchdown block were the predecessor of patch panels. punchdown
block used to be very common for 4 Mbps Token Ring and Ethernet networks,
but punchdown block generally aren't considered capable of supporting
Category 5 cabling. This section discusses punchdown block with Type 66
connectors, and their use for telephone or Local Talk networks.
66 punchdown block is used to handle telephone cabling. 66 punchdown block
solved the problem of how to connect several cable runs to each other,
without going through a hub.For example, One can have only one incoming
line from the phone company, but I needed to connect it to several different
rooms.
A 66 block is a punchdown block with type 66 connectors. A unique feature
of this 66 punchdown block was that it was prewired. Each 4 rows were
connected to 4 pins on an RJ-11 (phone) connector. If you do the math,
you'll see that with 4 rows used per RJ-45, with a 50 row block it has
12 RJ-11 connectors and 2 rows left over.
Column 4 is commonly used as an "outgoing" column, with each
row connected to a pin on a cable leading to a office drop. Column 1 is
used as an "incoming" column. To wire "straight through",
connecting pin 1 to pin 1, all you have to do is use a bridge clip to
connect column 2 to 3 on the row for pin 1. A bridge clip is just a little
metal clip just the right size to connect column 2 and 3 together. If
you need to crosswire something, just connect a wire from column 2 in
one row to column 3 in a different row.This neat and easy arrangement
has made 66 punchdown block very popular in telephone and network cable
management.
Also, notice that on an RJ-11 for telephone use, the pairs are different.
Pair
Colors
Use
1 Red and green Telephone line 1
2 Black & yellow Telephone line 2
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