IBM 3872 User Manual page 22

A. and B.
local loops
c.
Half-Duplex
Transmit Test
DTE
Modem
Modem
TPG
~
.......
-----------i
~
TPG
TPC
--tf/ ~
TPC
1-------------t
DTE
Operate Indicator
Operate Indicator
Modem Modem
Operate Indicator
Modem Modem
D.
Half-Duplex
Receive Test
1~
TPGI-
- - - - - D T - E -
.......-------11
TK
~I
(
~-----'
®Operate Indicator
DTE
E.
Duplex
Remote loop
DTE
Modem Modem
TPG
_....,,._-+----. . . . . . .
TPC __ ..,_ _ _ _ _ _ ,
Operate Indicator
Operate I ndi cat or
Note I: If the generated test pattern does not check prope'rl y at the receiver, the modem momentarily turns off the Operate indicator.
Note 2: Tests illustrated here are lettered to correspond with those described and lettered under "Modem Test Concepts
in Port I of this manual. Items C and D can be executed simultaneously in a duplex configuration. Item E
can be executed by the remote modem as well as by the local modem.
Note 3: Refer to IBM 3872 Modem Problem Determination GA27-3062, for specific switch setting and detailed
sequential test procedures.
TPG
=
test pattern generate
TPC = test pattern check
Figure 1-8. Modem Test Configurations
1-12 IBM 3872 Modem User's Guide
DTE