
Preliminary Data Sheet
T7230A Primary Access Framer/Controller
June 1997
26
Lucent Technologies Inc.
Frame Formats
(continued)
T1 Framing Structures
(continued)
D4 Frame Format
D4 superframe format consists of 12 DS1 frames. Table 9 shows the structure of the D4 superframe.
Notes:
The F bit of frame 1 is transmitted first.
Frames 6 and 12 contain the robbed-bit signaling information in bit 8 of each channel, when enabled for voice.
Signaling option none uses bit 8 for traffic data.
The remote alarm forces bit 2 of each time slot to a 0 state when enabled.
The remote alarm Japanese forces framing bit 12 (bit number 2123) to a 1 state when enabled.
The T7230A receive framer uses both the F
T
and F
S
framing bits during its frame alignment procedure. In addition,
a stomp mode may be programmed to set all processed receive signaling bits to a 1 state to reduce the possibility
of emulating the D4 framing pattern within the actual frame.
Digital Data Service (DDS) Frame Format
The superframe format for DDS is the same as that given for D4. DDS is intended to be used for data-only traffic,
and as such, the system should ensure that the T7230A is in the nonsignaling mode (TSIG = 1). DDS uses channel
24 to transmit the remote frame alarm and data link bits. The format for channel 24 is shown in Table 10.
Table 9. D4 Superframe Format
Framing Bits
Bit
Number
Bit Used in Each Time Slot
Traffic
(all
channels)
1—8
1—8
1—8
1—8
1—8
1—7
1—8
1—8
1—8
1—8
1—8
1—7
Signaling Options
None
2 State
Frame
Number
Terminal
Frame F
T
Signal
Frame
F
S
—
0
—
0
—
1
—
1
—
1
—
0
Remote
Alarm
Signal-
ing
4 State
1
2
3
4
5
6
7
8
9
0
1
—
0
—
1
—
0
—
1
—
0
—
2
2
2
2
2
2
2
2
2
2
2
2
—
—
—
—
—
8
—
—
—
—
—
8
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
A
—
—
—
—
—
A
—
—
—
—
—
A
—
—
—
—
—
B
193
386
579
772
965
1158
1351
1544
1737
1930
2123
10
11
12
Table 10. DDS Channel 24 Format
Channel 24 =
Y =
D =
10111YD0
Remote frame alarm: 1= no alarm state; 0 = alarm state
Data link bits (8 kbits/s)