6
Speed – Switches 1 and 2: TNE1500-P Only
The T1 line has 24 channels continuously running at 64 kbps for a collective bandwidth
of 1,536 kbps. The timeslot configuration determines how many of the channels for each
port will actually receive data. Ports configured to operate as fractional T1 lines require
contiguous timeslots as indicated in the table below.
Configuration Switches 1 and 2 on the TNE1500-P work together to provide four
timeslot/bandwidth options for the T1 link. The TNE1500-S determines timeslot and
bandwidth configurations for the T1 link via communication with its partner T1 provider
unit.
Frame Type – Switch 3
Frame type is the T1 data encapsulation method. A frame consists of 193 bits (8-bit
samples of each of the 24 T1 data channels, plus a synchronization bit) transmitted at a
rate of 8,000 frames per second (1,536 kbps) across the T1 line.
Extended Super Frame – Extended Super Frame (ESF) format, used in Wide Area
Networks (WANs), assembles data into 24-frame transmission clusters and
integrates the following:
—
Facilities Data Link: Facilities Data Link (FDL) provides in-service monitoring
and diagnostics.
—
Cyclic Redundancy Check: Cyclic Redundancy Check (CRC) scrutinizes data
integrity and detects line errors.
Super Frame – Super Frame (SF) format assembles data into 12-frame
transmission clusters. SF does not utilize FDL or CRC.
Table 3. T1 Speed Settings
Switch 1
Switch 2
Timeslots Bandwidth (kbps)
down
down
1–24
1,536
up
down
1–18
1,152
down
up
1–12
768
up
up
1–6
384
Table 4. Frame Type Settings
Switch 3
Frame Type
down
Extended Super Frame
up
Super Frame
