Types of 3270 terminals

The following types of 3270 terminals are directly supported by VTAM® in its domain:

SNA 3270 terminals:
Local (PU type 2): 3270 terminal attaches to a PU type 2 cluster controller, which in turn attaches to the VTAM host processor by a System/370 channel. Example: 3278 Display Station on 3274-1A Control Unit.
Remote SDLC (PU type 2): 3270 terminal attaches to a PU type 2 cluster controller, which in turn attaches by an SDLC link to a communication controller containing an NCP, or directly to a processor through a communication adapter. Example: 3278 Display Station on 3276 Control Unit.
Remote SDLC (PU type 1): 3270 terminal attaches to a PU type 1 cluster controller, which in turn attaches by an SDLC link to a communication controller containing NCP, or directly to a processor through a communication adapter. Examples: 3288 Line Printer on 3271-12 Control Unit or a 3767 terminal.

Non-SNA 3270 terminals:
Local: 3270 terminal attaches to a non-SNA cluster controller, which in turn attaches to the VTAM host processor by a System/370 channel. Example: 3277 Display Station on 3272 Control Unit. A 3270 terminal attached to a 4331 Display/Printer adapter also presents this appearance.
Remote BSC: 3270 terminal attaches to a non-SNA cluster controller, which in turn attaches by a BSC link to a communication controller containing NCP, or directly to a processor through a communication adapter. Example: 3286 Printer on 3271-2 Control Unit.

In addition, VTAM supports sessions between application programs in the VTAM host processor and 3270 terminals in another domain in which each cross-domain terminal provides the appearance of one of the types of 3270s listed in the preceding discussion.