IBM SC33-1683-02 - Manual (Page 738)

Device-dependent data
Dependent on the device: 3270, or other. See the following sections on the
relevant devices.
FMH Function management header.
SNA only = length in first byte
non-SNA = not applicable.
Message
User data.
TCAM with 3270 devices
The CCB and device-dependent data for an input message from TCAM to CICS
have the following format:
The CCB is present for TCAM SNA lines only.
The CCB and device-dependent data for 3270 output messages from CICS to
TCAM have the following format:
All SOH% status messages input to CICS are passed to DFHTACP or DFHTEP.
Terminal control copy and read buffer requests are not supported by the
CICS-TCAM interface.
In addition to normal read and write functions, the ERASEAUP, CTLCHAR, and
UCTRAN operands are also valid for the 3270.
All 3270 printer scheduling and error handling is provided by the TCAM message
handler.
Note: For 3270 SDLC devices, the escape character must be removed by the
message handler.
CCB1 CCB2 Attention CURSOR
1 byte 1 byte identifier 2 bytes
SNA only SNA only 1 byte
CCB1 CCB2 1 2 3
1 byte 1 byte 1 byte 1 byte 1 byte
(2 bytes - SNA) device-dependent data
(1 byte - non-SNA)
1 Escape character
2 Command
3 WCC (write control character)
TCAM devices
706 CICS TS for OS/390: CICS Customization Guide