Filter
Top Products
Character Length
In asynchronous data format, 10 and 11 bit characters are
supported. This setting is ignored in synchronous data format.
Character Character Description
SW1-6 Length Start Data bits Parity Stop bits
Off 10-bit 1 8 None 1 or more
1 7 1 1 or more
1 7 None 2
On 11-bit 1 8 1 1 or more
1 9 None 1 or more
Data Format
The data format selection controls whether an async-to-sync
conversion is performed. (Data is always transferred synchronously
between the two CSU/DSU’s)
SW1-7 Data Format
On Asynchronous
Off Synchronous
Note
1
: The async rate of 57.6 kbps is supported at the 56kbps line
rate, provided the DTE equipment transmits two stop bits. Two stop
bits can be configured on most DTE equipment. This extra stop bit
reduces the DTE’s effective data rate by a few percent to allow
synchronization with the 56kbps line speed.
Note
2
: Lower speed asynchronous data can be transmitted on
synchronous circuits by simple over-sampling. To do this, leave Data
Format set to synchronous. Make sure the CSU/DSU’s sync data rate
is at least 4 times more than the async data rate you wish to send.
DSR Loop Status
The behavior of the DSR output during performance of a local
loop can be controlled.
DSR
SW1-8 Loop Status Description
On DSR On DSR remains high (On) during the
Analog Loop
Off DSR Off DSR goes low (Off) during the
Analog Loop
4.1.2 SWITCH SET SW2
The configuration switches on switch SW2 control the Rate
Adapter/DTE Rate, Clock Mode, Anti-Stream Timer and RTS/CTS
Delay. Figure 5 (below) summarizes SW2 switch settings, including the
factory defaults. Following Figure 4 is a description of each switch
setting.
Rate Adapter/DTE Rate
The Model 2500 Series includes a rate adapter that allows the unit
to be used with DTE devices that support rates lower than 56/64 kbps.
All switch settings below are valid for line rates of 56 or 64 kbps.
SW2-1 SW2-2 SW2-3 DTE Rate
On On On 2.4 kbps
Off On On 4.8 kbps
On Off On 9.6 kbps
Off Off On 19.2 kbps
On On Off 38.4 kbps
Off Off Off Line Rate = DTE Rate
Note: for DTE devices that operate at 57.6 kbps, set the Line Rate to
56 kbps (see Section 4.1.1), set the rate adapter for “Line Rate=DTE
Rate”, and configure your DTE device for two stop bits (set character
length accordingly).
1211
SWITCH SET 2 SUMMARY TABLE
Figure 4. Summary of switch settings, showing factory defaults
Position Function Factory Default
Switch SW2-1
Rate Adapter/
Off
Switch SW2-2
DTE Rate
Off
Switch SW2-3 Off
Switch SW2-4 DTE
Loop Control
Off Disabled
Switch SW2-5 Clock
Mode
Off Off
Switch SW2-6 Off On
Switch SW2-7
Anti-Stream Timer
On Disabled
Switch SW2-8 RTS/
CTS Delay
Off Normal
Model 2510
Switched 56
}
Network
Clock
}
DTE Rate
}