IBM 3872 User Manual page 48

Feature
Second Modem
Point-To-Point
Multipoint Tributary
Switched Network
Switched Network Backup
Automatic Answering with Switched Network
Backup
Automatic
Call
Origination on Switched Network
Direct Line Attachment
Alternate Voice
Fan-Out
Legend:
does not apply
R receiver feature
T/R transmitter and receiver feature
X available option
Configurations
M-P Ctrl (Basic)
M-P Trib. (Feature)
P-P {Feature)
Sw. Network (Feature)
T/R
R
Feature Characteristics
Two modems {any combination of point-to-point,
multipoint, or switched network) in one cabinet.
Receiver equalization.
Transmitter and receiver equalization.
Manual calling, automatic answering.
Automatic receiver equaliz.ation requires 1020 ms
clear-to-send delay for first transmission, l85 ms ·
thereafter. Generates 3. 5-second 2100 Hz answe_r
tone.
Manual calling, manual answering.
Receiver equalization, requires 150 ms
clear-to-send de lay.
Makes unattended operation of DTE possible on
switched network. Generates 3.5-second
2100 Hz answer tone.
Two cables to DTE. Demand--response parallel
transfer of dial digits. Calls are programmed
by DTE. Includes automatic answering and
3.5-second 2100 Hz answer tone.
Line isolation transformer, one for 2-wire, two
for 4-wire modem.
Visual and audible signaling and voice
communication.
Allows up to three DTEs to use one
3872 Modem (one at a time ).
T/R_
x
x
x
x
x
x
x
x
x
x
x
x
x
Special
Features
Figure 3-7. Special Feature Characterislies and
Qua1i~fcations
3-14 IBM 3872 Modem User's Guide
Feature Qualifications
Excludes switched network backup and automatic
call origination on both modems.
Dedicated line.
Dedicated line.
Exdudes point-to-point and multipoint. Special
arrangement in WT countries.
Excludes Second Modem feature. Special arrange-
ment in WT co1;1ntries. See Appendix C for plan-
ning and operating considerations.
Special feature only with switched network
backup, standard with Switched Network feature.
Requires switched network, excludes Second
Modem feature, requires automatic answering
at called stations. EON option is not supported
by IBM programs at this time.
Presently required in some WT countries.
Requires a dedicated communications
channel. Telephone handset is not
provided.
Excludes Second Modem and Switched
Network features. Requires multipoint
programming for DTE addresses.
Features by
Modem Configuration
(see Figure 1-3)