3Com SuperStack II, NETBuilder SI manual Using the BRIDGE/ROUTER in Your Network

24CHAPTER 2: USING THE BRIDGE/ROUTER IN YOUR NETWORK

Using WAN and SuperStack II NETBuilder SI bridge/routers come with two or four serial

Serial Portsports and one of the following WAN ports: a built-in ISDN S/T terminal adapter (TA) (models 43x and 53x), a built-in ISDN U TA (models 44x and 54x), a built-in 56/64 Kbps CSU/DSU (models 45x and 55x) or a built-in T1/FT1 Telco port (models 46x and 56x).

ISDN Port (Model 43x, The ISDN port provides a basic rate interface (BRI). The BRI delivers two

53x, 44x and 54x) bearer (B) channels and one delta (D) channel. Each B channel can transmit up to 64 kilobits per second (kbps); the D channel transmits information about the call to computers at the switching system at a rate of 16 kbps. You can use both B channels together for a combined data rate of 128 kbps, or use each 64 kbps B channel separately.

Some ISDN lines support up to 56 Kbps per B channel. For more information, contact your ISDN service provider.

Order ISDN lines from the phone company. See Appendix E for more information about ordering ISDN lines.

Installations in Hong Kong should be configured to originate and receive ISDN calls at 64 Kbps. Due to the variety of ISDN switches in the Hong Kong Telcom network, the SuperStack II NETBuilder SI bridge/router does not handle rate adapted ISDN calls at 56 Kbps properly.

56/64K CSU/DSU Port A CSU/DSU is equivalent to a modem for a digital line. The 56/64K (Model 45x CSU/DSU port connects directly to a Digital Data Service (DDS).

and 55x)

Order DDS lines from the phone company. Contact your phone company for more information about DDS lines and the services available for them.

T1/FT1 CSU/DSU Port A CSU/DSU is equivalent to a modem for a digital line. The T1/FT1 (Model 46x and 56x) CSU/DSU port connects directly to a T1 line or a fractional T1 line.

Fractional T1 consists of 24 channels (DS0s) at 64 Kbps each, so you can connect to one or more DS0s with the T1/FT1 port.

Order T1 lines from the phone company. Contact your phone company for more information about T1 lines and the services available for them.