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Clock Mode
Choosing option 9 in the Software Switch Menu takes you to the
Clock Mode Menu (below).
Set this option as follows:
• Internal (Master): To use the Model 2500 Series internal reference
clock as the timing source, select item 1. Use internal timing in point-to-
point applications where the Model 2500 Series is being used as a
limited distance modem. (Set the far-end Model 2500 Series unit for
looped timing as described below.)
• Network (Looped): To have the Model 2500 or 2520 derive a
transmit clock from the incoming data stream from the network, select
item 2. This is the default setting and appropriate for most applications.
• External (Terminal Timing): To have the Model 2500 Series use the
DTE-supplied transmit clock (pin 24 on and RS-232/V.24 interface or
pins U and W on a V.35 interface), select item 3. Use external timing
for tail-circuit applications, in which the RS-232 or V.35 ports of two
Model 2500 Series units are interconnected.
• Switched 56 (Model 2510 and 2520 only): When using a Model
2510 or 2520 with Switched 56 service, select item 4.
(continued)
Anti-Streaming Timer
Choosing option “a” in the Software Switch Menu takes you to the
Anti Stream Timer Menu (below). (Note: You must use lower case
letters for options “a” thru “e”) This option lets you enable or disable the
anti-streaming timer, which protects multidrop networks from a drop that
is continuously transmitting. If the DTE asserts RTS for a period of time
exceeding the timer interface, the timer forces RTS off internally. This
allows the rest of the multidrop network to resume operation. The
Model 2500 Series holds RTS off until the terminal drops RTS. The
timer interval decreases as the line rate increases.
RTS/CTS Delay
Choosing option “b” in the Software Switch Menu takes you to the
RTS/CTS Delay Menu (below). This option lets you set the RTS/CTS
turn-on delay to Normal or Extended. The delay interval decreases as
the line rate increases.