Slide 11

Question 1

most common DS-1 framing

Answer 1

The two most common types of DS-1 framing are SF and ESF
Superframe
uses 12 frames per master frame
Extended Superframe
uses 24 frames per master frame thus
allowing extra signaling bits for additional features

Question 2

2 types of ways to deal with FCC with 8 consecutive 0’s

Answer 2

AMI uses Bit7 coding which jams
the lease significant bit of an
eight-bit word with a ones pulse whenever there are more then
eight consecutive zeros – decreases a 64kbps channel to 56kbps

B8ZS (Bipolar with eight-zero substitution) replaces eight
consecutive zeros with a four-bit code containing a bipolar
violation that is detected by the end equipment – substitution
does not use bandwidth

Question 3

ds-3 physical media

Answer 3

Since DS-3s are high-frequency, high-speed signals that required
a different medium then a DS-1
DS-3s use coax cable and is capable of 450 to 600 feet
DS-3s can be placed on microwave radios 3 per channel
Most often DS-3s are placed on fiber optic cable

Question 4

3 types of DS3 framing

Answer 4

1. M13 – similar to DS-1 framing
2. C-bit parity – has extra bits for monitoring
3. Unchannelized – same overhead bits as M13 framing but has
   no DS-2 or DS-1 framing