¹Digital Terminal Data Modules (DTDM), and Data Adaptors (DA) in linked mode are considered part of the Digital Line MO. See the DIG-LINE section for maintenance of these devices. DAs in stand-alone mode are included in PDMODULE.

Some of the alarms that are logged due to PDMODULE and TDMODULE test failures may be related to PROCR problems reported during DIG-BD testing.

Error log entries and tests also apply to TDMODULE.

The PDMODULE and TDMODULE MOs monitor and test Digital Line circuit pack ports that are connected to Data Communications Equipment (DCE) or Data Terminal Equipment (DTE). DCE include processor data modules (MPDM) and Data Adaptors (DA). DTE include trunk data modules (DTE). These stand-alone data modules provide interfaces between DCP ports on the Digital Line PROCR and data equipment such as terminals, host computers, and data modems. See the following list and figure. Data modules are used for dial-up and permanent circuit-switched data calls.

Digital Line PROCR also connect to digital terminal data modules (DTDMs), which work in conjunction with a voice terminal. Those configurations are covered by the DIG-LINE MO. PROCR level maintenance is covered by DIG-BD whose strategy is described in the XXX-BD (Common Port Circuit Pack/Media Module).

Digital line PROCR include the TN754, TN754B, TN413, TN2136. See DIG-LINE (Digital Line) for more information about the characteristics of these PROCR.