The SB-22A/PT is a lightweight, portable manual switchboard commonly used for local battery (LB) communications, remote controlled radio circuits and voice-frequency (VF) teletypewriter circuits. It is adaptable for all weather field use or mobile and fixed base military shelter operation. The switchboard provides facilities for interconnecting up to 12 separate voice frequency circuits. Operator headset-microphone included.

Features:

Small, lightweight and durable

Essential for all portable telephone switchboard installations

Handles up to 12 telephone calls

Equipped with night alarm

Tightly fitted front cover protects from the elements

Includes accessory kit MX-2915/PT containing one trunk jack, two line jacks and spare signal lamps in carrying case

Technical Characteristics:
Local Battery lines or trunks: 12
Common battery signaling trunk: 1
Ringing (manual) 20 cycles per second, 90-100 V (provided by hand ringing generator)
Protection: Lighting arrestor, each line or trunk
Power requirements:

Operator’s telephone: 3 Vdc (2 Batteries BA-30 or equivalent)

Night Alarm: 3 Vdc (2 batteries BA-30 or equivalent)
Size: 5 ¼ “ H x 12 ½” D x 16” W
Weight: 30 Lbs. (14 Kg)

Configurations Available:
1. Tandem Arrangement – a tandem arrangement of 2 SB-22A/PT’s can provide as many as 29 lines by substituting the TA-221 operators pack in one unit with 5 TA-222/PT line packs.
2. Additional Battery Lines – by substituting 5 telephone circuits, line packs TA-222/PT for the operators pack TA-221/PT, 5 additional battery of lines may be provided.
3. Battery Signaling Trunk – by substituting a telephone circuit trunkjack TA-326/PT for the line pack TA-222/PT, 5 additional battery of lines may be provided.
4. Dialing Capability – dialing capability can be provided by an optional tone signaling adapter TA-977 which when mounted and connected to the switchboard, provides 16 dial tone signaling capability for an operator with automatic dialing equipment such as a switchboard SB-3614 and N/TTC-36.