The SB-22

Picture of an SB-22

This is the SB-22 switchboard I used to connect the TA-1 and TA-312 telephone sets to. Typically, the switchboard was located at the Command Post (CP) and all lines out to the bunkers and various mobile offices were tied into it.

Description of the SB-22

Description of the SB-22

The SB-22 Switchboard is a small portable field type telephone switchboard equipped with 12 interconnecting voice-frequency circuits. It can be used to interconnect local-battery telephone circuits, remote-controlled radio circuits, and voice-frequency teletypewriter circuits. It's powered by four "D" Cell batteries. Connection between lines are made with plugs and retractable cords. Included with each switchboard is an MX-230 Accessory Kit containing subassemblies to increase the line capacity when the switchboard is operated in tandem with another SB-22. A subassembly (to provide a common battery trunk replacing one line unit) is provided. The H-144/U Headset-Microphone is provided with each SB-22.

To install the SB-22:
* Place the headset over your head so the receiver covers one ear.
* Position the transmitter directly in front of your mouth.
* Align the connector on your headset cord with the receptacle on the operator's pack. Push it into the connector and turn it to the right so it locks in place. NOTE: The spacing of the lugs around the inside of the connector determines the position of the connector.
* Clip the PUSH-TO-TALK SWITCH on the handset-headset to the front of your shirt. After inserting the plug of your operating cord into the operator's pack, place the push-to-talk switch into any (one) of the positions. When answering the calling party, watch the signals on the front of the line packs; the line signals turn from black to white. Follow the procedures below to answer the incoming call:
* Remove the plug of the operator's cord from the operator's jack and insert it into the jack that shows the white line signal (calling party's line signal).
* Obtain the called party's name or number from the calling party and then proceed to interconnect the parties.
* When connecting the calling party to the called party, pull out the cord in the calling party's line and insert the plug into the called party's line jack. Then, signal the called party by turning the hand-ringing generator rapidly for approximately 10 turns. Do NOT operate the RING BACK-PWR RING FWD switch to either position. Wait for the called party to answer. After the called party answers, remove the operator's plug from the called party's jack and insert it into the operator's jack. After the calling and called parties finish talking, both parties should ring off. The ring-off signal causes the calling party's line to turn white. If you should have to challenge the ring-off signal, remove the operator's plug from the operator's jack and insert it into the calling party's jack Ask the parties if they have finished. If no one answers, disconnect the circuit. Remove the operator's plug from the calling party's jack and insert it into the operator's jack. If the calling party disconnects before the called party answers or before the conversation is completed, you can ring back the calling party.You do this by removing the plug of the operator's cord from the operator's jack on the operator's pack and inserting it into the calling party's jack. Operate the RING BACK-PWR RING FWD switch to the RING BACK, turn the hand-ringing generator rapidly approximately 10 turns. Remove the operator's plug from the calling party's jack and insert it into the operator's jack when both parties answer.
* If the called party disconnects before the conversation is completed, remove the plug of the operator's cord from the operator's pack and insert it into the jack of the calling party's line jack Operate the hand-ringing generator rapidly about 10 turns. Remove the plug of the operator's cord from the jack of the calling party's line jack and insert it into the operator's jack on the operator's pack after both parties have answered.
* If you must leave the switchboard, move the visual and audible alarm switch from VIS to AUD. The alarm is silent on VIS, but audible on AUD. When the alarm is not required, place the VIS/AUD switch in the OFF position.
* To operate your switchboard in the dark, pull out on the lamp cap and turn the lamp on. Remember, though, when the lamp is lighting the switchboard, the night alarm cannot be used at the same time.

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This site was created by William Caldwell for an IST 250 class project.
Last Updated 12/01/11