The 3174 Model 22L is a rack-mounted local channel controller that supports the Enterprise Systems Connection (ESCON*) Channel interface for SNA and non-SNA attachment. The Model 22L supports up to sixty-four 3270 devices and twenty-four ASCII devices. A Type-1 Teleprocessing Communication Adapter with a customer-provided communications cable for Alternate IML backup capability is provided.

Terminal Attachment

The 3174 Establishment Controllers offer a wide variety of terminal attachments. They can be configured to connect terminals directly, via 3299 Terminal Multiplexers, via optional Terminal Multiplexer Adapters (#3103) and via optional Telephone Twisted Pair Terminal Multiplexer Adapters (#3105), or by a combination of these attachments.

The 3174 has an integrated four-port terminal adapter which permits up to four terminals to be directly attached, or by using one of the following, up to a maximum of 32 terminals can be attached:

• One to four 3299 Terminal Multiplexers
• One to four Terminal Multiplexer Adapter optional features (#3103)
• Any combination of up to four 3299 Terminal Multiplexers and Terminal Multiplexer Adapter optional features.
• One Telephone Twisted Pair Terminal Multiplexer Adapter (#3105)

3174 Model 12L attaches to the Enterprise Systems Connection (ESCON) Channel. The ESCON Channel is part of the Enterprise Systems Channel Architecture and includes:

• Fiber optic cabling, and transmission, and reception
• Dynamic connectivity through switched point-to-point topology and data flow
• Interconnectivity with other networks
• An I/O architecture that exploits fiber optic technology and the concept of dynamic connectivity.

3174 Model 22L can be located up to 3 kilometers away and can directly attach to the host processor. A maximum distance of up to 43 kilometers can be achieved with ESCON Directors. The physical media for the ESCON Channel is a 62.5/125 micron multimode fiber optic cable.