互通

to intercommunicate / to interoperate

mutual

to go through / to know well / (suffix) expert / to connect / to communicate / open / to clear / classifier for letters, telegrams, phone calls etc

classifier for an activity, taken in its entirety (tirade of abuse, stint of music playing, bout of drinking etc)

(idiom) mutual exchange of assistance; to benefit from each other's strengths and make up each other's shortfalls; to reciprocate with material assistance; to scratch each other's back

mutual exchange of assistance (idiom) / to benefit from each other's strengths and make up each other's shortfalls / to reciprocate with material assistance / scratch each other's back

interoperability (of communications equipment)