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Installing the VPN router 34
OnSite 2800 Series User Manual 2 • Hardware installation
The signal pin-outs for the Model 2821 X.21 interface are shown in table 6.
The the router’s X.21 interface is wired as a DCE. No DTE configuration is possible. The router’s X.21 inter-
face requires a cable with a male DB-15 connector. Attach the male DB-15 connector of the X.21 cable to the
female DB-15 connector on the router. Attach the other end of the cable to the X.21 connector on local
modem or multiplexer device.
Installing the T1/E1 twisted pair cables. The PRI is usually connected to a PBX or switch (local exchange
(LE)). Type and pin-outs of these devices vary depending on the manufacturer. In most cases, a straight-
through RJ-48C to RJ-48C can be used to connect to the PRI (see for E1 RJ-48C pin-out listing) with a PBX.
A cross-over cable is required to connect to an NT1, as illustrated in .
Figure 4. Rear panel of 2803K/EUI
Figure 5. Rear panel of 2803T/EUI
Table 7. Signal pin-outs for the X.21 interface on the OnSite 2800
Pin Signal Pin Signal
1 Frame Ground 8 Signal Ground
2 TXDa 9 TXDb
3 CNTa 10 CNTb
4 RXDa 11 RXDb
5 INDa 12 INDb
6 SETa 13 SETb
Table 8. RJ-48C receptacle
Pin Signal
1 TX tip
2 TX ring
3 TX shield
4 RX tip
5 RX ring
6 RX shield