HP 600 Series, Services And Applications

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Physical Connections
Synchronous ports on HP routers physically function as DTEs.
Similarly, the synchronous ports on most devices, such as IBM 3270 cluster
controllers and HP network interfaces, physically function as DTEs. Thus,
the generally recommended practice is to connect these interfaces together
using modems or modem eliminators (see figure 5).
Figure 5. Modem Eliminators and Modems Used to Connect Synchronous Devices
to an HP Router
A low-cost alternative to a modem or modem eliminator is a null-modem
cable. A null-modem cable can be used instead of a pair of modems or a
modem eliminator when the device to be attached to the router is located
close by. Pin-outs for some null-modem WAN cables are shown in figures 6
and 7 for the HP routers. Figure 6 is for cables that can be attached directly
to the router’s 62-pin connector, and have either a V.35 or RS-232/V.24/V.28
interface. Making these cables requires a DB-62 connector on the router end.
Figure 7 is for a V.35 cable that can be attached to the V.35 WAN cable that
can be ordered with the HP router. Making the cable requires two standard
M/34 V.35 connectors,which may be more readily available. The clock source
on the HP router synchronous interface must be configured for “internal”
when using these null-modem WAN cables.
Extended LAN
Internetwork
HP 3000
Modem
Eliminator
19.2 KBIT/S
Router
Modem
Modem
9.6 KBIT/S
IBM 3174
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Using Synchronous Pass-Through to Consolidate Synchronous Traffic
Physical Connections
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