Toshiba Perfecptione Installation And Maintenance Manual page 341

AlTACHMENT A
Tl/DS-1 INTERFACE
The DS-1 interface operates at the rate of 1.544
Mbps. This rate is obtained by either one of the
following two methods:
METHOD 1:
l
Rate of each channel (time slot) = 64 kbps
l
64 kbps * 24 channels = 1.536 Mbps
l
Rate required for synchronization = 8 kbps
l
DS-1 rate = 1.536 Mbps + 8 kbps = 1.544 Mbps
METHOD 2:
l
8 bits per channel * 24 channels = 192 bits
l
1 bit for frame synchronization
l
Total bits in one frame = 193 bits
l
DS-1 rate = 193 bits * 8000 sampling rate per
second = 1.544 Mbps
In order to provide the above capabilities,
PERCEPTIONe,e, Tl/DS-1 digital trunk interface
shall comply with the requirements defined by the
industry for DS-1 service. The specified require-
Tl/DS-1
SEPTEMBER i&j
ments are shown in the following paragraphs.
DS-1 Service Requirements
Physical Interface: The physical interface must
comply with the defined specification for Tl/DS-I
frame and signaling format, pulse density restric-
tion, and electrical characteristics.
Frame and Signaling Format: As mentioned in
Method 2, the DS-1 frame format consists of 24 8-
bit words and one framing bit for synchronization,
which yields 193 bits per frame. The frames are
grouped into multiframes. These multiframes are
referred to as Super-frame (see Figure 1).
Superframe Grouping Format: Super-frame can
be grouped in two ways:
1) Twelve frames per Super-frame (SF). This
grouping is known as the D3/D4 Framing
Format.
l
In this arrangement the framing bit is used
only for synchronization.
l
The synchronization identifies the begin-
ning of the Super-frame and the signaling
I
1
FRAME
I
Y
125
MICROSECONDS
w
I
193 BITS
I
,
I
FRAMING
BIT
(1 BIT)
FIGURE l-FRAME ASSEMBLY