CANOGA PERKINS 2240 Fiber Optic Modem User Manual
Page 32
2240 Fiber Optic Modem User Manual
Chapter 3 Mode and Rate Selection
Operating Mode, Data Rate Selection
32
For many modes, the specific data rate must be selected. The data rate is selected by setting
four switches on the front panel (positions 1-4). Refer to Table 3-2 and Table 3-3 for the data rate
switch settings.
Table 3-1. Mode Switch Positions
Mode
DIP Switches
(C) Closed (O) Open
Operating Mode
5
6
7
0
C
C
C
Sampled External Clock up to
1.544 Mbps
1
O
C
C
Internal Clock Group 1 Rate
2
C
O
C
Internal Clock Group 2 Rate
3
O
O
C
Internal Clock Group 3 Rate
4
C
C
O
Internal Clock Group 4 Rate
5
O
C
O
Slave Clock
6
C
O
O
Asynchronous up to 1.500
Mbps *
7
O
O
O
External clock with variable
lock ratios (refer to Table 3-2)
* Frequency Limit assumes that user's equipment can tolerate 250 ns of
pulse distortion on the clock signal.
Table 3-2. Locked External Rates
Rate
DIP Switches (C) Closed (O) Open
Allowable Range of External
Clock Frequency (Mode 7)
Rate Switches
Range Select
1
2
3
4
8
0
C
C
C
C
C (Normal)
1.490 MHz to 2.060 MHz
O (Low)
1.026 MHz to 1.480 MHz
1
O
C
C
C
C (Normal)
750 kHz to 1.025 MHz
O (Low)
513 kHz to 749 kHz
2
C
O
C
C
C (Normal)
375 kHz to 512.5 kHz
O (Low)
256.3 kHz to 374 kHz
3
O
O
C
C
C (Normal)
187.5 kHz to 256.2 Hz
O (Low)
128 kHz to 187 kHz