(2) SB-22/PT and SB-22A/PT are tactical manual switchboards They can provide service to 12
local-battery telephone circuits. The operator can stack two SB-22s to support up to a 29-circuit system.
To support 29 subscribers, the operator must remove the operator pack from the second SB-22. He then
installs a 5-line pack. To interface with the automatic switches, the operator must install a TA-997/PT
or tone-signaling adapter. No operator intervention is required when using the tone-signaling adapter.
(See Appendix A, Figure A-10.)
(3) SB-3082(V) /GT can service up to 50 telephone circuits. The SB-3082 can be mounted on a
1/4-ton truck or in a shelter. The operator can set up a conference call for up to six subscribers. The
switchboard has an emergency power system. The emergency power system runs on two 12-volt
batteries. In addition, the switchboard brings a battery charger for recharging the emergency system.
(See Appendix A, Figure A-11.)
(4) AN/TTC-38 can interconnect 300 or 600 telephone circuits. We can find the AN/TTC-38
deployed in an area communications center (ACC). The AN/TTC-38 is all analog. The primary
telephones used with the AN/TTC-38 are the TA-341, TA-838, and the TA-938. Today, we find most
of the AN/TTC-38s still in service with the Reserve Component units. (See Appendix A, Figure A-14.)
(5) AN/TTC-39A and AN/TTC-39D can service 600 or 672 trunks depending on the model on
hand. The AN/TTC-39A provides, for the first time, the capability of miring analog and digital service.
It can interface with existing tactical switches (manual and automatic), commercial central offices, and
Defense Switched Network (DSN). In addition, the AN/TTC-39A and AN/TTC-39D can interface with
North Atlantic Treaty Organization (NATO) telephone systems. We find the AN/TTC-39D at EAC.
(See Appendix A, Figures A-15a through A-15d.) The AN/TTC-39A is found in Army Reserve EAC
(6) AN/TTC-41 and AN/TTC-41A is an automatic switchboard. The AN/TTC-41 comes in
several models. The AN/TTC-41(V) 1 can service up to 30 subscribers; the models V2 and V5 can
service up to 60 subscribers; the models V3 and V6 can service up to 90 subscribers; and the AN/TTC-
41A (V) 4 and 7 can service up to 120 subscribers. (See Appendix A, Figure A-16.) The AN/TTC-41A
can interface with the DSN and dial central offices (DCOs). The switchboard is capable of providing 2-
or 4-wire service.
(7) AN/TTC-46 or large extension node (LEN) switchboard has basically the same configuration
as the node center switch (NCS)(AN/TTC-47). The basic difference is the termination configuration for
trunks and loops. The LEN doctrinally is deployed in support of the division support command
(DISCOM) in an MSE division. It can support a total of 164 subscribers using J-1077 and remote
multiplexer combiners (RMCs). (See Appendix A, Figures A-17a and A-17b.)
(8) AN/TTC-47 or NCS is the hub of the MSE node. The AN/TTC-47 provides network
interface for the subscriber access elements. The AN/TTC-47 provides automatic subscriber finding,
deleting the need for knowledge of the subscribers' geographical location. (See Appendix A, Figures A-
18a and A-18b.)