We don't yet have enough information to say whether this is hearsay or whether it is admissible. Even among lawyers, a hearsay analysis is tricky, so I'm not surprised you're getting such loopy and inconsistent answers here.
A proper hearsay analysis moves in three steps:
Step 1: Is it an out-of-court statement offered to prove the truth of the matter asserted?
We have a roughly uniform definition of hearsay in courts across the United States. From Federal Rule of Evidence 801:
(c) Hearsay. “Hearsay” means a statement that:
(1) the declarant does not make while testifying at the current trial or hearing; and
(2) a party offers in evidence to prove the truth of the matter asserted in the statement.
So the first question we have to ask is why the statement is being offered. If the testimony is meant to prove merely that the witness and the defendant knew each other, or that the phones were working that day, or something eles, then the statement is not hearsay and it should come in. But if it's meant to prove that the defendant had, in fact, signed two deals and hired a new accountant, then you're within the general definition of hearsay and have to move on to Step 2.
Step 2: Is it the statement of an opposing party or the witness's own prior statement?
If the statement is being offered to prove the truth of the matter asserted, then you move on to see whether it fits into an exclusion from the definition of hearsay. The relevant question here is which attorney is directing the witness. If the plaintiff's attorney is asking the questions, the defendant's statement is almost certainly going to come in as "An Opposing Party’s Statement":
(2) An Opposing Party’s Statement. The statement is offered against an opposing party and:
(A) was made by the party in an individual or representative capacity;
(B) is one the party manifested that it adopted or believed to be true;
(C) was made by a person whom the party authorized to make a statement on the subject;
(D) was made by the party’s agent or employee on a matter within the scope of that relationship and while it existed; or
(E) was made by the party’s coconspirator during and in furtherance of the conspiracy.
But if the defense attorney is trying to bring out the witness's recollections of his own client's prior statements, you're still within the definition of hearsay, and you have to move on to Step 3.
Step 3: Does it fit within an exception to the rule against hearsay?
Even if a statement is hearsay, it may be admissible if it falls within one of many exceptions to the rule against hearsay. The first two listed in Rule 803 are possible fits:
(1) Present Sense Impression. A statement describing or explaining an event or condition, made while or immediately after the declarant perceived it.
Was the phone call made just as the deals closed or just as the defendant signed the accountant? If so, the statemnet can likely come in as a present-sense impression.
(2) Excited Utterance. A statement relating to a startling event or condition, made while the declarant was under the stress of excitement that it caused.
Were the two business deals the defendant closed particularly large or otherwise of such a character that they could be described as "startling" or "exciting"? Was the conversation had while the defendant was still excited about them? If so, then the statement may be admissible.