ASM-20 Short Range Modem from RAD
The ASM-20 Short Range Modem operates synchronously or asynchronously (strapselectable) at full or half duplex over
unconditioned lines. It has a range of up to 23 km (14 miles) and operates at data rates from 19.2 kbps up to 256 kbps. The use of
conditioned diphase modulation (EUROCOM Std. D1) provides immunity to background noise, eliminates normal line distortion and
enables efficient transmission and reception of serial data over twisted pair cable. Transmit timing is provided internally, or is
derived externally from the data terminal or receive signal. Receive timing is regenerated from the data. When set to async mode,
RAD ASM-20 performs async to sync conversion in compliance with ITU V.14 standard. Table 1 of product data sheet details the
rates relevant for sync and async. Rates higher than 115.2 kbps are supported in sync mode only.
ASM-20 features V.54 diagnostic capabilities to perform local analog loopback, and local and remote digital loopback. The
loops can be manually activated from the front panel or via control signals from the interface connector. In addition, ASM-20
incorporates a built-in Bit Error Rate Tester (BERT) to enable complete testing of both modems and the line. A front panel switch
generates a pseudo-random test pattern (511 bits) according to ITU V.52, for testing end-to-end
connectivity. An ERROR LED flashes when a bit error is detected.
ASM-20 is available as a desktop unit or as a card for the RAD ASM-MN-214
modem rack. The rack can carry up to 14 ASM-20 cards and is supplied with 25-pin D-type connectors.
ASM-20 Short Range Modem product data sheet
(pdf)
Optional hardware is available for mounting one or two standalone RAD ASM-20 units in a 19” rack.
Commonly ordered ASM-20 models:
ASM20-2/115/530 6012250000
ASM20-2/115/G.703/RJ 6012320000
ASM20-2/115/G703/TB 6012150000
ASM20-2/115/UTP 6012040000
ASM20-2/115/V24 6012020000
ASM20-2/115/V35 6012000000
ASM20-2/115/V36 6012340000
ASM20-2/115/X21 6012010000
ASM20-2/230/530 6012170000
ASM20-2/230/G.703/RJ 6012160000
ASM20-2/230/G703/TB 6012140000
ASM20-2/230/UTP 6012050000
ASM20-2/230/V24 6012120000
ASM20-2/230/V35 6012030000
ASM20-2/230/X21 6012110000
ASM20-2/24/UTP 6010060000
ASM20-2/48/UTP 6010070000
ASM20-2/48/V35 6012370000
ASM20-2/48/V36 6010190000
ASM20-2/48/X21 6012350000
ASM20-2R/530 6012070000
ASM20-2R/V24 6012130000
ASM20-2R/V35 6010280000
ASM20-2R/V36 6012090000
ASM20-2R/X21 6012100000
